The Twelve-coin Problem
A more complex version exists where there are twelve coins, eleven of which are identical and one of which is different, but it is not known whether it is heavier or lighter than the others. This time the balance may be used three times to isolate the unique coin and determine its weight relative to the others.
Read more about this topic: Balance Puzzle
Famous quotes containing the word problem:
“How much atonement is enough? The bombing must be allowed as at least part-payment: those of our young people who are concerned about the moral problem posed by the Allied air offensive should at least consider the moral problem that would have been posed if the German civilian population had not suffered at all.”
—Clive James (b. 1939)