Cans

Written on 11:44 pm by Vja Students

A company gets 16 cans of paint each month. The problem is that one of the 16 cans is always contaminated with lead. Fortunately, the company has the capacity to test for lead. However, due to time and money constraints, the results of the tests cannot be made known until after all of the tests have been performed. What is the fewest number of cans that must be tested in order to know for certain which of the 16 cans is contaminated.

Answer: It can be done in a maximum of 4 tests by mixing samples from half of the cans and then testing that mixture. If positive, the other half of the cans are dismissed and ifnegative that set of cans is dismissed. Repeat three times for the remaining cans.

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6 Comments

  1. Anonymous | 25 February 2008 at 12:09 am

    Does lead contamination changes weight of can? If yes then max. 3 weighings.

     
  2. Anonymous | 25 February 2008 at 4:44 pm

    4 cans

     
  3. Unknown | 25 February 2008 at 10:27 pm

    is it depends on weight???

     
  4. Complexity. Incarnated! | 26 February 2008 at 1:54 am

    whats the criteria for finding the faulty one?
    without knowing that..

    it cannot be found out..

     
  5. sreeraju | 26 February 2008 at 12:35 pm

    U have asked no. of cans to be used, but not the number of experiments...

     
  6. Unknown | 26 February 2008 at 8:16 pm

    some controversy exist...
    first one is as said by sreeraju...!!
    second one is if u mix 2 cans and test how come you arrive at 4 cans from 16???

    even if its 4 tests......at d worst case[take it for eg],we go for 4 tries...we find the 4th test as faulty one.As it has mix of 2 cans...again we ll ve to test wch one is faulty???

     

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