Answer to Question #336 in Algebra for qing-nian

Question

There are several bags with lots of coins in each. In one of them all coins are brum and in all the others they are real. The weight of a real coin is known and also it is known that the fake coin is 1 gram lighter than the real one. How is it possible to define the bag with the fake coins with the help of just one weighing in the scaled scales?

Answer 1

Enumerate the bags and take from each bag as many coins as its number is. Weigh these coins. Their weight is less than the weight of the same amount of real coins on the same amount of grams as the number of bag with the fake coins is.