# The Answer to Columbo’s Puzzle

I almost forgot to give you the answer to Columbo’s puzzle.

To recap: You have three bags filled with gold pieces, but the pieces in one of the bags are counterfeit. The only way you can tell the difference is that the genuine gold pieces weigh a pound apiece, but each counterfeit piece weighs one pound and one ounce. You need to discover which bag contains the counterfeits: but all you have, by way of equipment, is an old-fashioned penny scale, like they used to have in drugstores, and a single penny. How do you do it?

Well, no one here came up with the answer, so here it is.

From Bag #1 take one piece; from Bag #2, take two pieces; and from #3, three.

Weigh all six pieces at once.

If it weighs six pounds, one ounce, the counterfeits are in Bag 1. If it weighs six pounds, two ounces, they’re in Bag 2; if six pounds, three ounces, Bag 3.

1. Durn, you’re smart! I hadn’t even thought of that. For some reason, it never occurred to me to open the bags.

2. Phoebe says:

I’d thought of taking individual coins out of the bags, but I was counting on the penny scale being the kind that would adjust itself downward if part of the object on the scale was removed, so we could tell when the extra ounce disappeared as the coins were knocked off the scale one by one. Those scales were rare, though, and I was too lazy to look up when and where they were used. Anyway, I would never have thought of Columbo’s solution.

3. Thanks for the solution – now I can go right to sleep at night 🙂

4. g says: