Riddles

Here’s a cool little one to roll around for the weekend. Three and only three people, Jack, Amy, and George, are sitting at a table. – Jack is looking at Amy. – Amy is looking at George. – Jack is married. – George is unmarried. Question: Is a married person looking at an unmarried person? [...]

A doozy. Using a single straight line to the left of the equals sign, make the following statement true: 5+5+5=550 Think about this one. It’s worth it. There are two correct answers. If you give up (but don’t!), you can go google it.

You are presented with ten burlap bags full of coins. Nine of these bags contain counterfeit coins; one bag contains real gold coins. A counterfeit coin is visually identical to a real coin, and you do not know which bag contains the real gold. Each counterfeit coin weighs exactly 1 gram, while each real gold [...]

A classic exercise in creative thinking, with a solution that offers the essence of how to think about design. Your task: Without taking pen off paper, and using only four straight lines, connect the nine dots. I’ll post the answer in a few days.

One thousand students stand in line outside a school, each numbered 1 to 1000. In the school are one thousand closed lockers, each numbered 1 to 1000. One by one, the students go into the school and “change the state” of the lockers. That is, if a locker is open, they close it; if it [...]