Odd Ball Puzzle Instructions:

A snooker table factory produces snooker balls for their normal tables and special competition snooker balls. The competition balls are almost identical to the normal balls, but are very, very, slightly lighter in weight. There is a special machine to weigh the balls and select the competition balls during the production line run.

Unfortunately, today the weighing machine has broken down and an important competition is about to start that needs balls right now!

You have been asked to sort the balls but the only weighing equipment available is a set of old balance scales. The balls arrive in batches of 9, with one of those being a competition ball (but you don't know which one).

Because of the production line speed, you only have enough time to make TWO measurements. Also make sure that the method you use will work every time...

Can you do it?

In the interactive puzzle above, you can drag and drop the balls onto the scales and then press the blue "measure" button to weigh them. You can also drag the ball that you think is the lightest to the bottom right-hand blue square to see if you have correctly picked the right one.

This puzzle is also available as a print-out using PDF files.

The puzzle can be found here [PDF file 275 kB]

The solution can be found here [PDF file 208 kB]