You've got eight ball bearings in front of you all of which look absolutely identical.

However, one weighs slightly more than all the others due to a heavier material at its core. It has been mixed up with the other ball bearings by mistake and it's your job to find it as quickly as possible.

All you've got is an old fashioned set of counterbalance scales. What would be the fewest number of weighings you would need to do in order to find the heavier ball bearing?

Scroll down for the answer.

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The answer is just two!

Take any six of the eight ball bearings and put three on each side of the scale. If the heavy ball isn't in the group of six, you know it's one of the remaining two and so you put those two on the scale and determine which one is the heavier.

If the heavy ball bearing is in the six, you have narrowed it down to three. Of those three, pick any two and put them on the scale. If the heavy ball is in that group of two, you know which one it is. If both balls are of equal weight, then the heavy ball bearing is the one you put at the side.