Please briefly explain why you feel this question should be reported .


You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, how can you determine which coin is counterfeit using the scale only twice?

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Puzzle Admin 4 years 2 Answers 1072 views 0

Answers ( 2 )

  1. Please briefly explain why you feel this answer should be reported .


    First put 3 coins each side if it shows balance both side then put remaining two and which side will down means than coin is heavy.
    Case-2 if puting 3 coins each side we get one side heavy it means heavy coin is on that side so now we have to find heavy from 3 so now out 2 out of 3 on balance scale if equal then remaining one is heavy otherwise which side is heavy that coin will be heavy.

  2. Please briefly explain why you feel this answer should be reported .


    There are 8coinns. We can seperate the coins into 3 groups
    8 coins= 3 coins(group1) + 3coin (gr
    oup2) + 2 coins(group3)
    So counterfeit can be definitely in above 3 groups
    Case 1:
    First scale group1 and group 2
    1. If both group weighs the same counterfeit is in 3 rd group
    2. If group2 weighs more, counterfeit in grp2
    3 . Else counterfeit in grp3

    We hav used scale once till now

    If case 1 satisfies……
    1.a now scale 3 rd grp which hav only 2 coins to find counterfeit

    If case2 satisfies
    2.a scale b/w first grp 3 coins. similar to first 3 cases

    If case 3 satifies scale b/w 3 rd group similar to 2.a

    Hence we can find counterfeit using scale 2 tymz

    Best answer

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