| October 10, 2008 12:38:38 |
#3 |
| Himanshu Ashwani |
Member Since: October 2008 Total Comments: 2 |
RE: In 80 coins one coin is counterfiet what is minimum number of weighings to find out counterfiet coin?
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The answer is 4
Divide Coins As 27 27 26
now weigh 27 and 27 keeping on both sides of pan u will get the less one
and if both sides are equal then group that has 26 coins has the coin that is counterfiet...
if u get 27 as result divide it in 3 groups
9 9 9
and weight it
keep two groups on two sides of pans and get the result of both sides are equal then the group 9 which was not kept on the pan has the coin which is counterfiet....
now 9 is divided as in 3 groups as
3 3 3 and weigh again and get result
now divide 3 as
1 1 1 and get the coin..
in start if u get answer as 26 divide as 3 groups
9 9 8
wiegh by keeping 9 on both sides and get answer if both are equal then 8 is ans
if 9 is ans again divide as 3 3 3 and then 1 1 1 and get coin...
if u get 8 then divide as 2 2 2 then 1 1 less one be yours coin... |
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