Originally posted by AMEN567889:
There are 10 sets of 10 coins. You know how much the coins should weigh. You know all the coins in one set of ten are exactly a hundredth of an ounce off, making the entire set of ten coins a tenth of an ounce off. You also know that all the other coins weight the correct amount. You are allowed to use an extremely accurate digital weighing machine only once.
How do you determine which set of 10 coins is faulty?
1st set take out 1 coin. 2nd set take out 2 coins and so on till the 9th set. then put all together at once. this suppose to be the correct answer. but i got a question, what if the coins you took out is faulty?

can't determine which set le.
