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Brain Teaser Part 2 RRS feed

Answers

  • Pouring water IV.
    How can you measure 6 litres of water using only 4 and 9-litre bowls.
    Sunday, June 10, 2007 12:30 PM
  • Let the 9 litre bowl be A and the other one be B

     

    A(9)     B(4)

    9          0        Fill A

    5          4        A->B

    5          0        Empty out B

    1          4        A->B

    1          0        Empty out B

    0          1        A->B

    9          1        Fill A

    6          4  (1+3)   A->B

     

     

    Now A contains 6  litres of water...

     

    Sunday, June 10, 2007 4:34 PM
  • nice work.. i was just wondering, can we have a program which calculates the minimum number of steps if we input the number of bowls, their capacity and our required amount???
    Sunday, June 10, 2007 5:43 PM
  • Pouring water V.
    Measure exactly 2 litres of water if you have:
    1. 4 and 5-litre bowls
    2. 4 and 3-litre bowls

    Hey this is avery easy one, specially for the people who havent been trying their hands on it...
    @ Adnan, Arijit and Raghuram, please wait till the 1pm tommorow, then post the answer... lets see if anyone else can answer it.. its the simplest one yet.. if you have been observing the previous questions and answers, you can easily answer this...
    Sunday, June 10, 2007 5:51 PM
  • Thanks Varun for starting a new thread. The other one was getting harder to navigate.
    Sunday, June 10, 2007 6:28 PM
  • Damn i am too bad at these Sad
    Sunday, June 10, 2007 6:41 PM
  • @Varun, Well I did post after 1:00 pm.

    Soln 1:

    1) Fill the 5-litre bowl
    2) Fill the 4-litre bowl from the 5-litre bowl
    3)Empty the 4-litre bowl
    4)Thus we have 1 litre in the 4-litre bowl, now fill the 5-litre bowl and pour it in the 4-litre bowl (where there is already 1 litre).
    5)Now you have 2 litres in the 5-litre bowl.

    Soln 2:

    1) Fill the 3-litre bowl  and pour it into the 4-litre bowl.
    2) Fill the 3-litre bowl again fill the 4-litre bowl (Where there is 3-litre remaining)
    3) Thus you have 2 litres in the 3-litre bowl.
    Monday, June 11, 2007 8:15 AM
  • This seems to easy, i just dont know why i wasn't able to think about it ;P
    May be i didn't wanted to use my brain.
    Monday, June 11, 2007 8:59 AM
  • Hey don't say that...There is nothing wrong with you, Your rank and your point say everything.

    It is just that your knack is at something else. I have never seen you falter at any of the pogramming threads.
    Best of luck to you and my wishes that you may win this contest hands down.
    Monday, June 11, 2007 9:04 AM
  • Hey Harshil, dont worry, you will get used to it after some practice.. just try this one out...

    Pouring water VI.
    -
    Imagine having three bowls. In the bowl A (8 litres capacity) are 5 litres of water. In the bowl B (5 litres capacity) are 3 litres of water. In the bowl C (3 litres capacity) are 2 litres of water.
    Can you measure exactly 1 litre, pouring only 2 times?
    Monday, June 11, 2007 2:46 PM
  • A   B   C
    5   3   2   Initial
    7   3   0   (C->A)
    8   2   0   (B-A)

    Now B will have 2 litres Stick out tongue

    I thin i am getting started Stick out tongue
    Monday, June 11, 2007 5:10 PM
  • Well, no Harshil.. The question was to get exactly 'one' litre, not 2... Smile
    I think this will do (though I don't know whether to count the number of 'pourings' to be 2 or 3)..
    * Pour a litre of water from 8 ltr bowl to 3 ltr bowl (pour till it gets filled) and discard the water in 3 ltr bowl.
        =>Now 8 ltr bowl has 4 ltrs.
    * Pour 3 ltrs from 8 ltr bowl to 3 ltr one.
        =>Now 8 ltr bowl has 1 ltr.
    Geez, I didn't use the 5 ltr bowl at all.. Probably there's a better solution..
    Monday, June 11, 2007 5:51 PM
  • Well, as i had not mentioned that you dont have to waste the water, you answer would be valid...

    But lets put the condition that you are not suppose to waste the water, so now try to get 1ltr in 2 pouring....

    @Harshil, dont worry, you got 2, now you will get 1 also.. try again...
    Monday, June 11, 2007 6:40 PM
  • A(8)   B(5)    C(3)

    5         3          2      (Initially)

    4         3          3      (A->C)

    4         5          1      (C->B)

     

     

    As simple as that...

    Tuesday, June 12, 2007 9:08 AM
  • Good  questions in this thread , i will join soon ,
    Tuesday, June 12, 2007 11:09 AM
  • Rajkumar, this thread is indeed very nice. and great mind twisting questions. Hope you join after your exams are over Wink Will be waiting for you.
    Tuesday, June 12, 2007 12:31 PM
  • Sand-glass I.
    Having 2 sand-glasses: one 7-minute and the second one 4-minute. How can you correctly time 9 minutes.
    Tuesday, June 12, 2007 2:36 PM
  • Let A be the 7minute sandclock and the other be B

     

    1)Both the sandcolocks are allowed to start.

    2)When all sand from B has fell into the lower chamber, immediately turn it upside down...

    3)When all sand from A has fell into the lower chamber, immediately trun B upside down.

    4)The count starts form then.. When sand has fell from one chamber of B to another, 1 minute would have passed by.. Turn it upside down immediately..

    5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn B upside down again..

    6)When the sand has been transferred completley this time, 9 minutes would have passed by...

     

    (Though more than 9 minutes would have passed due to the small delays caused in turning the sand clocks)

     

    Tuesday, June 12, 2007 5:00 PM
  •  

    My calculations give me 18 minutes Raghu. Am I wrong somewhere?

    >1)Both the sandcolocks are allowed to start.

    >2)When all sand from B has fell into the lower chamber, immediately turn it upside down...

     

    4 minutes over

     

    >3)When all sand from A has fell into the lower chamber, immediately trun B upside down.

     

    7 minutes over, B has 3 minutes' sand in upper chamber

     

    >4)The count starts form then.. When sand has fell from one chamber of B to another, 1 minute

    >would have passed by.. Turn it upside down immediately..

     

    As I said, it seems 3 minutes, not 1 minute, would have passed by in this step. So totals to 10 already.

     

    >5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn

    >B upside down again..

    10+4 = 14

     

    >6)When the sand has been transferred completley this time, 9 minutes would have passed by...

    14+4 = 18 

     

      ??
    Tuesday, June 12, 2007 5:15 PM
  • Ok guy, there was a small error in my previous answer..  Now, i'll post the corrected solution...

     

     

    Let A be the 7minute sandclock and the other be B

     

    1)Both the sandcolocks are allowed to start.

    2)When all sand from B has fell into the lower chamber, immediately turn it upside down...(3 minutes  of sand remaining in A)

    3)When all sand from A has fell into the lower chamber, start the count... (1 minute of sand remaining in B)

    4) When sand has fell from one chamber of B to another, 1 minute would have passed by.. Turn it upside down immediately..

    5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn B upside down again..

    6)When the sand has been transferred completley this time, another 4 minutes would have passed by...

     

     

    Now B's timing after A's completition is 1+4+4 =9 minutes

    (Though more than 9 minutes would have passed due to the small delays caused in turning the sand clocks)

    Tuesday, June 12, 2007 5:31 PM
  • Oh.. I'm very sorry. I ignored the 'count starts from then' part as I couldn't understand what it meant.
    While reading Raghu's answer, I got a somewhat simpler solution. But most of the work had been done by Raghu, so the credit for the answer goes to him I think. Smile
    1) Start both A(7 min) and B(4 min) (0 minutes over)
    2) When B finishes (+4 min), turn it upside down
    3) When A finishes (+3 min), turn A upside down
    4) When B finishes (+1 min), turn A upside down
    5) Allow A to finish (+1 min).
    So 0+4+3+1+1 = 9 min.

    Hope I've not screwed up again...

    Tuesday, June 12, 2007 5:49 PM
  • Raghuram, I had thought of the same answer before, but then i found a better answer to it....

    So there is a better answer to it....
    Tuesday, June 12, 2007 5:51 PM
  • Well guys, I had been talking to the owner of the site from where i m posting this questions..
    I asked for his permission to post the questions from his site here in our forums, He gave the permission and asked to mention his site name....

    So Special thanks to the brainden.com site owner for giving out such a wonderful questions...

    Please do visit the site for new questions and get registered.. I will continue to post more questions from the site here, but will really like if you guys try to solve the problem on your own and do not refer to the site for the answer....

    So once again Special thanks to
    brainden.com

    Its a wonderful site with lots of questions, and we will have a part of it here in the MS Forums...
    So do visit the site.... (but not for answers to the questions posted here)
    Tuesday, June 12, 2007 5:57 PM
  • Damn i am hating this alert feature, it stopped working, and while i am back to resolve the problem, i already see the solution done by Raghuram Stick out tongue hehe

    Next one please
    .

    Tuesday, June 12, 2007 6:00 PM
  • Actually , i wanted you to come up with solution ... Hence , i didn't answer when i saw the question first.. But when i came back again after 1 hour, it was  still left unanswered , so i thought i would try my hands at the question..
    Wednesday, June 13, 2007 12:55 AM
  • A much simpler solution than mine.. Good work Sundar.. Welcome to the forums Sundar..
    Wednesday, June 13, 2007 12:58 AM
  • @Sundara, that was the answer i was expecting, good work...
    Wednesday, June 13, 2007 3:48 AM
  • Sand-glass II.

    A teacher of mathematics used an unconventional method to measure time for a test lasting 15 minutes. He used just a sand-glass, which spills in 7 minutes and a second sand-glass, which spills in 11 minutes. During the whole time he turned sand-glasses only 3 times. Explain how the teacher measured 15 minutes.

    Wednesday, June 13, 2007 3:52 AM
  • Start the 7 min and 11 min sand glasses.
    When the 7 min sand glass has stopped, start the timing procedure (That is how we will be able to get the measurement of 11-7 = 4 min).
    After the 11 min one as finished, restart it again. Thus, with 4 min for prev one and 11 min now, we have mesaured 4+11= 15 min.
    Wednesday, June 13, 2007 12:17 PM
  • Time for some Matchstick problems..
    Try to rectify a mistake by moving a single matchstick, to get the correct equation.
    Wednesday, June 13, 2007 1:21 PM
  • The following equation is made of 11 matches:
    XI - V = IV
    Wednesday, June 13, 2007 1:24 PM
  •  XI - V = VI

     

    Thursday, June 14, 2007 2:01 AM
  • Ther's another possible solution

    It  is IX -V = IV

    Thursday, June 14, 2007 2:01 AM
  • Good work Raghuram.. there is one more possibility to the question...
    IX - VI = V
    Thursday, June 14, 2007 4:28 AM
  • Time for the next one....
    The following equation is made of 11 matches:
    X + V = IV
    Thursday, June 14, 2007 4:29 AM
  •  Varun_Modi_a59ed9 wrote:
    Good work Raghuram.. there is one more possibility to the question...
    IX - VI = V

     

    You have a small mistake there.. It should have been XI - VI =V

    Thursday, June 14, 2007 4:45 AM
  • There's a fourth solution too IX - IV =V
    Thursday, June 14, 2007 4:46 AM
  • the matchsticks one are nice, let more coming, i missed few yesterday as i was out of town.
    Thursday, June 14, 2007 4:57 AM
  • Actually i dont know what to do, can you please give one example, and solution of it with explanation ?
    Thursday, June 14, 2007 6:09 AM
  •  Harshil_Patel_03b5f2 wrote:
    Actually i dont know what to do, can you please give one example, and solution of it with explanation ?


    Ok, let me give the example of the one already soved above...

    just imagine that the equation below is made of the matchsticks..
    XI - V = IV

    There will be 11 matchsticks used in the above equation....
    Now you are suppose to move just one Matchstick, i.e. one stick from above to make the euqation correct...
    XI - V = IV the equation means
    11 - 5 =  4  Not correct...
    I move one matchstick
    IX - V = IV
    9  -  5  =  4

    Now the equation is correct... This way you are suppose to solve the questions.. now try out this one

    X + V = IV
    Thursday, June 14, 2007 1:52 PM
  • Original :
    X + V = IV
    Answer
    X - VI = IV
    10-6=4

    now i have got it right Wink let more of em coming now ): ill try to solve them, they are fun.
    Thursday, June 14, 2007 2:42 PM
  • There is one more solution to it...
    Thursday, June 14, 2007 4:36 PM
  • Original:
        X + V = IV
    Answer #2:
        IX - V = IV

    There are a few other answers like taking a matchstick from + or IV and placing on the equals sign - making it 'not equal'.. But that's probably not an expected answer I think. Smile
    Thursday, June 14, 2007 5:33 PM
  •  Raghuram_Duraisamy_ed4912 wrote:
    There's a fourth solution too IX - IV =V

     

     

    oops, i made a small mistake here.. This is not one of the answers since it requires two matches to be moved ...

    Friday, June 15, 2007 12:47 AM
  • Yup, you are right,, that was not expected, but your answer is right....

    Ok time for some more like this..
    The following equation is made of 12 matches:
    VI = IV - III
    Friday, June 15, 2007 4:05 AM
  • @Varun - Why wasn't that expected ? is there another solution too to that ?

    Anyways, let me try the other solution

    VI = IV - III



    Solution :
    VI = IV + II
    6 = 4 + 2
    Friday, June 15, 2007 4:14 AM
  • @Harshil I was not refering to you
    I said that making the equation as not equal to was not expected....

    Okk.. there is one more answer to it.. its a bit tricky one but find out...

    by then here is the new question...

    As today is a special day, I will post a new question at a gap of 2 hrs...
    So next question will be at 2pm...

    1)
    The following equation is made of 14 matches:
    XIV - V = XX

    2)
    The following equation is made of 11 matches:
    IX - IX = V

    3)
    The following equation is made of 12 matches:
    X = VIII - II
    Friday, June 15, 2007 6:50 AM
  • To 1) alone:

    XIV - V = XX

    becomes

    XV + V = XX

    Friday, June 15, 2007 7:08 AM
  • To 3):

    X = VIII - II

    becomes

    X - VIII = II

    Friday, June 15, 2007 7:10 AM
  • A possible answer to 2) is:

    IX - IX = V

    becomes

    IX - IV = V

                       where the / matchstick from the second X is taken and placed slightly to the right... Is this right Varun?

    Friday, June 15, 2007 7:14 AM
  • Yup, thatz right.. good work...
    Friday, June 15, 2007 9:02 AM
  • She-goat, Wolf and Cabbage
    A farmer is returning from market, where he bought a she-goat, a wolf and cabbage. On the way home he must cross a river. His boat is little, allowing him to take only one of the three things. He can't keep the she-goat and the cabbage together (because the she-goat would eat it), nor the she-goat with the wolf (because the she-goat would be eaten).
    How shall the farmer get everything on the other side (without any harm)?
    Friday, June 15, 2007 9:17 AM
  • * Take the goat and place him on the other side (leaving wolf and cabbage in side 1)

    * Take the wolf and go to the other side, place the wolf and take back the goat.

    * Place the goat on side 1, and take the cabbage to the other side (so goat is in side 1, wolf and cabbage are in side 2).

    * Now take the goat to side 2.

               Hope this is right...

    Friday, June 15, 2007 11:46 AM

All replies

  • Pouring water IV.
    How can you measure 6 litres of water using only 4 and 9-litre bowls.
    Sunday, June 10, 2007 12:30 PM
  • Let the 9 litre bowl be A and the other one be B

     

    A(9)     B(4)

    9          0        Fill A

    5          4        A->B

    5          0        Empty out B

    1          4        A->B

    1          0        Empty out B

    0          1        A->B

    9          1        Fill A

    6          4  (1+3)   A->B

     

     

    Now A contains 6  litres of water...

     

    Sunday, June 10, 2007 4:34 PM
  • nice work.. i was just wondering, can we have a program which calculates the minimum number of steps if we input the number of bowls, their capacity and our required amount???
    Sunday, June 10, 2007 5:43 PM
  • Pouring water V.
    Measure exactly 2 litres of water if you have:
    1. 4 and 5-litre bowls
    2. 4 and 3-litre bowls

    Hey this is avery easy one, specially for the people who havent been trying their hands on it...
    @ Adnan, Arijit and Raghuram, please wait till the 1pm tommorow, then post the answer... lets see if anyone else can answer it.. its the simplest one yet.. if you have been observing the previous questions and answers, you can easily answer this...
    Sunday, June 10, 2007 5:51 PM
  • Thanks Varun for starting a new thread. The other one was getting harder to navigate.
    Sunday, June 10, 2007 6:28 PM
  • Damn i am too bad at these Sad
    Sunday, June 10, 2007 6:41 PM
  • @Varun, Well I did post after 1:00 pm.

    Soln 1:

    1) Fill the 5-litre bowl
    2) Fill the 4-litre bowl from the 5-litre bowl
    3)Empty the 4-litre bowl
    4)Thus we have 1 litre in the 4-litre bowl, now fill the 5-litre bowl and pour it in the 4-litre bowl (where there is already 1 litre).
    5)Now you have 2 litres in the 5-litre bowl.

    Soln 2:

    1) Fill the 3-litre bowl  and pour it into the 4-litre bowl.
    2) Fill the 3-litre bowl again fill the 4-litre bowl (Where there is 3-litre remaining)
    3) Thus you have 2 litres in the 3-litre bowl.
    Monday, June 11, 2007 8:15 AM
  • This seems to easy, i just dont know why i wasn't able to think about it ;P
    May be i didn't wanted to use my brain.
    Monday, June 11, 2007 8:59 AM
  • Hey don't say that...There is nothing wrong with you, Your rank and your point say everything.

    It is just that your knack is at something else. I have never seen you falter at any of the pogramming threads.
    Best of luck to you and my wishes that you may win this contest hands down.
    Monday, June 11, 2007 9:04 AM
  • Hey Harshil, dont worry, you will get used to it after some practice.. just try this one out...

    Pouring water VI.
    -
    Imagine having three bowls. In the bowl A (8 litres capacity) are 5 litres of water. In the bowl B (5 litres capacity) are 3 litres of water. In the bowl C (3 litres capacity) are 2 litres of water.
    Can you measure exactly 1 litre, pouring only 2 times?
    Monday, June 11, 2007 2:46 PM
  • A   B   C
    5   3   2   Initial
    7   3   0   (C->A)
    8   2   0   (B-A)

    Now B will have 2 litres Stick out tongue

    I thin i am getting started Stick out tongue
    Monday, June 11, 2007 5:10 PM
  • Well, no Harshil.. The question was to get exactly 'one' litre, not 2... Smile
    I think this will do (though I don't know whether to count the number of 'pourings' to be 2 or 3)..
    * Pour a litre of water from 8 ltr bowl to 3 ltr bowl (pour till it gets filled) and discard the water in 3 ltr bowl.
        =>Now 8 ltr bowl has 4 ltrs.
    * Pour 3 ltrs from 8 ltr bowl to 3 ltr one.
        =>Now 8 ltr bowl has 1 ltr.
    Geez, I didn't use the 5 ltr bowl at all.. Probably there's a better solution..
    Monday, June 11, 2007 5:51 PM
  • Well, as i had not mentioned that you dont have to waste the water, you answer would be valid...

    But lets put the condition that you are not suppose to waste the water, so now try to get 1ltr in 2 pouring....

    @Harshil, dont worry, you got 2, now you will get 1 also.. try again...
    Monday, June 11, 2007 6:40 PM
  • A(8)   B(5)    C(3)

    5         3          2      (Initially)

    4         3          3      (A->C)

    4         5          1      (C->B)

     

     

    As simple as that...

    Tuesday, June 12, 2007 9:08 AM
  • Good  questions in this thread , i will join soon ,
    Tuesday, June 12, 2007 11:09 AM
  • Rajkumar, this thread is indeed very nice. and great mind twisting questions. Hope you join after your exams are over Wink Will be waiting for you.
    Tuesday, June 12, 2007 12:31 PM
  • Sand-glass I.
    Having 2 sand-glasses: one 7-minute and the second one 4-minute. How can you correctly time 9 minutes.
    Tuesday, June 12, 2007 2:36 PM
  • Let A be the 7minute sandclock and the other be B

     

    1)Both the sandcolocks are allowed to start.

    2)When all sand from B has fell into the lower chamber, immediately turn it upside down...

    3)When all sand from A has fell into the lower chamber, immediately trun B upside down.

    4)The count starts form then.. When sand has fell from one chamber of B to another, 1 minute would have passed by.. Turn it upside down immediately..

    5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn B upside down again..

    6)When the sand has been transferred completley this time, 9 minutes would have passed by...

     

    (Though more than 9 minutes would have passed due to the small delays caused in turning the sand clocks)

     

    Tuesday, June 12, 2007 5:00 PM
  •  

    My calculations give me 18 minutes Raghu. Am I wrong somewhere?

    >1)Both the sandcolocks are allowed to start.

    >2)When all sand from B has fell into the lower chamber, immediately turn it upside down...

     

    4 minutes over

     

    >3)When all sand from A has fell into the lower chamber, immediately trun B upside down.

     

    7 minutes over, B has 3 minutes' sand in upper chamber

     

    >4)The count starts form then.. When sand has fell from one chamber of B to another, 1 minute

    >would have passed by.. Turn it upside down immediately..

     

    As I said, it seems 3 minutes, not 1 minute, would have passed by in this step. So totals to 10 already.

     

    >5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn

    >B upside down again..

    10+4 = 14

     

    >6)When the sand has been transferred completley this time, 9 minutes would have passed by...

    14+4 = 18 

     

      ??
    Tuesday, June 12, 2007 5:15 PM
  • Ok guy, there was a small error in my previous answer..  Now, i'll post the corrected solution...

     

     

    Let A be the 7minute sandclock and the other be B

     

    1)Both the sandcolocks are allowed to start.

    2)When all sand from B has fell into the lower chamber, immediately turn it upside down...(3 minutes  of sand remaining in A)

    3)When all sand from A has fell into the lower chamber, start the count... (1 minute of sand remaining in B)

    4) When sand has fell from one chamber of B to another, 1 minute would have passed by.. Turn it upside down immediately..

    5)After another 4 minutes , the sand would have fell completley from one chamber to another.. Turn B upside down again..

    6)When the sand has been transferred completley this time, another 4 minutes would have passed by...

     

     

    Now B's timing after A's completition is 1+4+4 =9 minutes

    (Though more than 9 minutes would have passed due to the small delays caused in turning the sand clocks)

    Tuesday, June 12, 2007 5:31 PM
  • Oh.. I'm very sorry. I ignored the 'count starts from then' part as I couldn't understand what it meant.
    While reading Raghu's answer, I got a somewhat simpler solution. But most of the work had been done by Raghu, so the credit for the answer goes to him I think. Smile
    1) Start both A(7 min) and B(4 min) (0 minutes over)
    2) When B finishes (+4 min), turn it upside down
    3) When A finishes (+3 min), turn A upside down
    4) When B finishes (+1 min), turn A upside down
    5) Allow A to finish (+1 min).
    So 0+4+3+1+1 = 9 min.

    Hope I've not screwed up again...

    Tuesday, June 12, 2007 5:49 PM
  • Raghuram, I had thought of the same answer before, but then i found a better answer to it....

    So there is a better answer to it....
    Tuesday, June 12, 2007 5:51 PM
  • Well guys, I had been talking to the owner of the site from where i m posting this questions..
    I asked for his permission to post the questions from his site here in our forums, He gave the permission and asked to mention his site name....

    So Special thanks to the brainden.com site owner for giving out such a wonderful questions...

    Please do visit the site for new questions and get registered.. I will continue to post more questions from the site here, but will really like if you guys try to solve the problem on your own and do not refer to the site for the answer....

    So once again Special thanks to
    brainden.com

    Its a wonderful site with lots of questions, and we will have a part of it here in the MS Forums...
    So do visit the site.... (but not for answers to the questions posted here)
    Tuesday, June 12, 2007 5:57 PM
  • Damn i am hating this alert feature, it stopped working, and while i am back to resolve the problem, i already see the solution done by Raghuram Stick out tongue hehe

    Next one please
    .

    Tuesday, June 12, 2007 6:00 PM
  • Actually , i wanted you to come up with solution ... Hence , i didn't answer when i saw the question first.. But when i came back again after 1 hour, it was  still left unanswered , so i thought i would try my hands at the question..
    Wednesday, June 13, 2007 12:55 AM
  • A much simpler solution than mine.. Good work Sundar.. Welcome to the forums Sundar..
    Wednesday, June 13, 2007 12:58 AM
  • @Sundara, that was the answer i was expecting, good work...
    Wednesday, June 13, 2007 3:48 AM
  • Sand-glass II.

    A teacher of mathematics used an unconventional method to measure time for a test lasting 15 minutes. He used just a sand-glass, which spills in 7 minutes and a second sand-glass, which spills in 11 minutes. During the whole time he turned sand-glasses only 3 times. Explain how the teacher measured 15 minutes.

    Wednesday, June 13, 2007 3:52 AM
  • Start the 7 min and 11 min sand glasses.
    When the 7 min sand glass has stopped, start the timing procedure (That is how we will be able to get the measurement of 11-7 = 4 min).
    After the 11 min one as finished, restart it again. Thus, with 4 min for prev one and 11 min now, we have mesaured 4+11= 15 min.
    Wednesday, June 13, 2007 12:17 PM
  • Time for some Matchstick problems..
    Try to rectify a mistake by moving a single matchstick, to get the correct equation.
    Wednesday, June 13, 2007 1:21 PM
  • The following equation is made of 11 matches:
    XI - V = IV
    Wednesday, June 13, 2007 1:24 PM
  •  XI - V = VI

     

    Thursday, June 14, 2007 2:01 AM
  • Ther's another possible solution

    It  is IX -V = IV

    Thursday, June 14, 2007 2:01 AM
  • Good work Raghuram.. there is one more possibility to the question...
    IX - VI = V
    Thursday, June 14, 2007 4:28 AM
  • Time for the next one....
    The following equation is made of 11 matches:
    X + V = IV
    Thursday, June 14, 2007 4:29 AM
  •  Varun_Modi_a59ed9 wrote:
    Good work Raghuram.. there is one more possibility to the question...
    IX - VI = V

     

    You have a small mistake there.. It should have been XI - VI =V

    Thursday, June 14, 2007 4:45 AM
  • There's a fourth solution too IX - IV =V
    Thursday, June 14, 2007 4:46 AM
  • the matchsticks one are nice, let more coming, i missed few yesterday as i was out of town.
    Thursday, June 14, 2007 4:57 AM
  • Actually i dont know what to do, can you please give one example, and solution of it with explanation ?
    Thursday, June 14, 2007 6:09 AM
  •  Harshil_Patel_03b5f2 wrote:
    Actually i dont know what to do, can you please give one example, and solution of it with explanation ?


    Ok, let me give the example of the one already soved above...

    just imagine that the equation below is made of the matchsticks..
    XI - V = IV

    There will be 11 matchsticks used in the above equation....
    Now you are suppose to move just one Matchstick, i.e. one stick from above to make the euqation correct...
    XI - V = IV the equation means
    11 - 5 =  4  Not correct...
    I move one matchstick
    IX - V = IV
    9  -  5  =  4

    Now the equation is correct... This way you are suppose to solve the questions.. now try out this one

    X + V = IV
    Thursday, June 14, 2007 1:52 PM
  • Original :
    X + V = IV
    Answer
    X - VI = IV
    10-6=4

    now i have got it right Wink let more of em coming now ): ill try to solve them, they are fun.
    Thursday, June 14, 2007 2:42 PM
  • There is one more solution to it...
    Thursday, June 14, 2007 4:36 PM
  • Original:
        X + V = IV
    Answer #2:
        IX - V = IV

    There are a few other answers like taking a matchstick from + or IV and placing on the equals sign - making it 'not equal'.. But that's probably not an expected answer I think. Smile
    Thursday, June 14, 2007 5:33 PM
  •  Raghuram_Duraisamy_ed4912 wrote:
    There's a fourth solution too IX - IV =V

     

     

    oops, i made a small mistake here.. This is not one of the answers since it requires two matches to be moved ...

    Friday, June 15, 2007 12:47 AM
  • Yup, you are right,, that was not expected, but your answer is right....

    Ok time for some more like this..
    The following equation is made of 12 matches:
    VI = IV - III
    Friday, June 15, 2007 4:05 AM
  • @Varun - Why wasn't that expected ? is there another solution too to that ?

    Anyways, let me try the other solution

    VI = IV - III



    Solution :
    VI = IV + II
    6 = 4 + 2
    Friday, June 15, 2007 4:14 AM
  • @Harshil I was not refering to you
    I said that making the equation as not equal to was not expected....

    Okk.. there is one more answer to it.. its a bit tricky one but find out...

    by then here is the new question...

    As today is a special day, I will post a new question at a gap of 2 hrs...
    So next question will be at 2pm...

    1)
    The following equation is made of 14 matches:
    XIV - V = XX

    2)
    The following equation is made of 11 matches:
    IX - IX = V

    3)
    The following equation is made of 12 matches:
    X = VIII - II
    Friday, June 15, 2007 6:50 AM
  • To 1) alone:

    XIV - V = XX

    becomes

    XV + V = XX

    Friday, June 15, 2007 7:08 AM
  • To 3):

    X = VIII - II

    becomes

    X - VIII = II

    Friday, June 15, 2007 7:10 AM
  • A possible answer to 2) is:

    IX - IX = V

    becomes

    IX - IV = V

                       where the / matchstick from the second X is taken and placed slightly to the right... Is this right Varun?

    Friday, June 15, 2007 7:14 AM
  • Yup, thatz right.. good work...
    Friday, June 15, 2007 9:02 AM
  • She-goat, Wolf and Cabbage
    A farmer is returning from market, where he bought a she-goat, a wolf and cabbage. On the way home he must cross a river. His boat is little, allowing him to take only one of the three things. He can't keep the she-goat and the cabbage together (because the she-goat would eat it), nor the she-goat with the wolf (because the she-goat would be eaten).
    How shall the farmer get everything on the other side (without any harm)?
    Friday, June 15, 2007 9:17 AM
  • * Take the goat and place him on the other side (leaving wolf and cabbage in side 1)

    * Take the wolf and go to the other side, place the wolf and take back the goat.

    * Place the goat on side 1, and take the cabbage to the other side (so goat is in side 1, wolf and cabbage are in side 2).

    * Now take the goat to side 2.

               Hope this is right...

    Friday, June 15, 2007 11:46 AM
  • again some more readings and complex ones Stick out tongue
    Friday, June 15, 2007 2:20 PM
  • Dark Phobia
    One family wants to get through a tunnel. Dad can make it in 1 minute, mama in 2 minutes, son in 4 and daughter in 5 minutes. Unfortunately, through the tight tunnel can go at once not more than two persons moving at the speed of the slower one.
    Can they all make it if they have a torch that lasts only 12 minutes and they are afraid of the dark?
    Friday, June 15, 2007 3:21 PM
  • * Dad and Mama go (2 minutes)

    * Mama returns (+2 min)

    * Son and daughter go (+5 min)

    * Dad returns (+1 min)

    * Dad and Mama go (+2 min)

    2+2+5+1+2 = 12 minutes...

    Friday, June 15, 2007 3:59 PM
  • answer for 2:

    IX - IX = V

    becomes

    IX - IV = V


    Friday, June 15, 2007 4:51 PM
  • Flowers
    How many flowers do I have if all of them are roses except two, all of them are tulips except two, and all of them are daisies except two?
    Saturday, June 16, 2007 4:57 PM
  • 3 flowers - 1 tulip, 1 rose and 1 daisy.

     

     

    Sunday, June 17, 2007 12:58 AM
  • in total, 3 flowers.
    one each of rose, tulip & daisy
    Sunday, June 17, 2007 11:53 AM
  • Total 3 flowers

    One of each kind Wink
    Sunday, June 17, 2007 3:45 PM
  • Round vs. Square
    Why is it better for manhole covers to be round rather than square?
    Monday, June 18, 2007 4:31 PM
  • Because round is easier to make, and also mark . It only want Radius and you measure it from the center point . WHile in square you have to do more measurements to mark the center point and then other things as well.
    Monday, June 18, 2007 4:42 PM
  • The main reason for the manhole covers to be in circular shape is to prevent the cover from slipping into the hole..

    Suppose the hole was a square one, then the lid can be slipped in by putting it vertically along the diagonals of the square.. Whereas such thing cannot happen in a circular manhole..
    Monday, June 18, 2007 5:31 PM
  • well, lid which is used to cover up the hole can easily slip into the square hole diagonally but in case of circular holes, it's practically & theoretically impossible.
    that's why circular holes are preferred
    Tuesday, June 19, 2007 4:15 AM
  • The Barbershop Puzzle
    A traveler arrives in a small town and decides he wants to get a haircut. There are only two barbershops in town - one on East Street and one on West Street. The East Street barbershop is a mess, and the barber has the worst haircut the traveler has ever seen. The West Street barbershop is neat and clean, its barber's hair looks as good as a movie star's.
    Which barbershop does the traveler go to for his haircut, and why?
    Tuesday, June 19, 2007 4:41 AM
  • Well...It is a fact that, no Barber cuts his/her own hair. Hence, if there are only 2 barbers in town, they have to cut each others hair. The West Street Barber has done a bad job on the orther one, but the East Street Barber has done a good job. Hence, the customer should go to the East Street Barber.
    Tuesday, June 19, 2007 5:30 AM
  • What is being described in this riddle? When I am filled,
    I can point the way.
    When I am empty,
    Nothing moves me.
    Tuesday, June 19, 2007 5:31 AM
  • Is it a compass ???
    When its fill with water, it can point the way, when its empty, it cannot move to point to any direction....

    And Arijit, please change the subject line while giving the new question.. so that we can easily track the answers...
    Tuesday, June 19, 2007 2:42 PM
  • I too think its a compass Smile
    Tuesday, June 19, 2007 3:58 PM
  • Well the answer is a GLOVE however, personally I think, a COMPASS can also be the right answer.
    Tuesday, June 19, 2007 4:42 PM
  • what's that which when goes inside is hard & long but when comes outside becomes soft & mushy/ & short 2
    keep guessing
    Wednesday, June 20, 2007 10:17 AM
  • Is it a chewing gum???
    Wednesday, June 20, 2007 11:01 AM
  • How about a Sugarcane.....
    Wednesday, June 20, 2007 3:36 PM
  • nope buddy.
    it's not soft when taken outside.
    right answer is chewing gum.
    another problem.

    i come once in a year.
    twice in a month
    4 times in a week
    & 6 times in a day.
    what am i?
    Thursday, June 21, 2007 9:17 AM
  • Ghost ?

    Thursday, June 21, 2007 4:54 PM
  • haha, nice try, but that is not the answer.. i had heard of a similar problem before but m not able to recall the answer..
    Thursday, June 21, 2007 6:19 PM
  • nope buddy.
    keep guessing
    Friday, June 22, 2007 3:53 AM
  • anyonefound out the answer ?

    Friday, June 29, 2007 4:19 PM
  • we are still waiting for the right answer....
    Friday, June 29, 2007 10:46 PM
  • @Sunil - Better give out the answer..
    Saturday, June 30, 2007 1:48 AM
  • how long will we have to wait for the answer Stick out tongue
    Thursday, July 5, 2007 3:33 AM
  • its simply the numbers of letters used in words

    ONCE=YEAR
    4=4
    TWICE=MONTH
    5=5
    FOUR=WEEK
    4=4
    SIX=DAY
    3=3

    Monday, September 3, 2007 6:21 PM
  • hey great reply.
    Hats off to you, Swati.

    Tuesday, September 4, 2007 1:47 AM
  • Good one swati Wink You solved it, or you knew the solution earlier ?
    hahah, if you solved it then i am really impressed Smile
    Tuesday, September 4, 2007 6:43 PM
  • Yup.. good going... so lets start with the puzzles again.. i will search for more and others also search for it....
    Wednesday, September 5, 2007 4:07 AM
  • hey man, the puzzles was really a good thing, lets start the brain teasers again Smile
    Wednesday, September 5, 2007 12:58 PM
  • i enjoyed the teaser.
    keep coming up with new ones varun...
    Wednesday, September 5, 2007 1:59 PM
  • Chandru was very fond of biscuits. So his mom made 3 bottles of biscuits:
    1 containing cream biscuits alone
    1 containing salt biscuits alone
    1 containing both types of biscuits
    She prepared labels for the bottles: 'Cream', 'Salt' and 'Mixed'. Fixing her concentration on the India-England match, she placed the wrong labels on all the bottles...
    She told Chandru about this, and asked him to find which bottle contains what.
    * Chandru is not allowed to look inside the bottles.
    * He can only take one biscuit from one of the bottles and taste it.
    With that, he has to identify all the 3 bottles correctly...
    Is it possible? Can you help him?
    Thursday, September 6, 2007 8:11 AM
  • Nice one... But its easy.. it can be done in one step only....
    Pick up a biscuit from the jar labled as MIX
    Now as all the jars are marked incorrectly.. That jar can not be a mixed one... so if you get a cream buscuit than its the jar with cream buscuits only and the other way round....

    so let us consider we get a cream buscuit...
    Label : S       C       M
    Jars  :                    C

    Now as other jars are also marked incorrectly, The jar marked as the cream buiscuit has either mixed or salted.....
    If it has mixed then
    Label : S       C       M
    Jars  :           M        C
    Then the jar marked as salted has salted buscuit, which is correct and so not possible...
    So the jar marked as salted has Mixed and jar marked as Cream has Salted buscuits...
    Label : S       C       M
    Jars  :  M       S       C

    We considered the mix jar to have Cream.. if its salt than ans would be
    Label : S       C       M
    Jars  :  C       M      S


    It was a nice one.. let more come in,....
    Thursday, September 6, 2007 4:24 PM