Mr Smith has lots of pound coins, ten boxes in all. Each box contains 100 pound coins, but one box contains coins which are all counterfeit and are
slightly lighter, 1/16 of an ounce lighter to be exact. The problem lies in the fact that they all look identical, the only way to tell them apart is to weigh them. Mr Smith knows the correct weight for a box, but how many weighings are required to determine which box contains the counterfeit ones?