How do you determine which stack is counterfeit with only one weighing?
Monday, October 26th, 2009 at
5:51 pm
there are 10 stacks of 10 gold coins, each coin 2 ounces. one stack is counterfeit each coin 1 ounce.
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Tagged with: Gold Coins • Ounce • stack • stacks
Filed under: Trivia
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take 1 coin from stack 1
2 coins from stack 2
3 coins from stack 3
etc.
weigh the coins.
they will weigh a little less than 110 ounces
the number of ounces less than 110 ounces
is the counterfeit stack
take 1 coin from the first stack,2 from the second,3 from the third and so on and thus in one weighing you will know which stack is counterfeit
Put 1 coin from the first stack on the scale, 2 from the second stack, 3 from the third stack, etc… That’s a total of 55 coins on the scale. If they were all good the weight would be 110 ounces.
If there’s 1 ounce missing (109) then there’s one bad coin so it comes from the first stack.
108 would mean 2 bad coins, so 2nd stack. Etc.