Ten bags of coins. One bag has fakes — each fake is 1g lighter than a real coin.
You have a digital scale, but only ONE weighing.
How do you find the bag of fakes?

Question

Accepted Answer

Take 1 coin from bag 1, 2 from bag 2, 3 from bag 3 … 10 from bag 10. Weigh together. If the scale reads X grams less than expected, X is the fake bag’s number. — The shortfall acts like a signature. Bag 7 fakes? You’re short 7g. The scale spells out the answer in a single reading.

Ten bags of coins. One bag has fakes — each fake is 1g lighter than a real coin. You have a digital scale, but only ONE weighing. How do you find the bag of fakes?