|Brain Warm-up||Based on My Best Mathematical and Logic Puzzles|
You are given eight stacks of coins, a pointer scale (one that tells the
weight) and the following knowledge. Figure out which stack of coins is
counterfeit in the minimal number of weighings and explain the procedure used.
|Only 1 weighing is necessary if you, first, set the stacks down in a row and name them stack zero through seven. Then you weigh a single group of coins comprised of 0 coins from stack 0, 1 coin from stack 1, 2 from 2, 3 from 3, and so on. The total extra weight in grams (above 28*[genuine coin weight]) is the counterfeit stacks number.|