Responses/hints to Puzzle #11

If you used the hint to let r = 1 in., then the tennis balls each have volume

(4/3)pi in³, so 4 balls have total volume (16/3)pi in³.

Since the tube/can has the same radius as the balls, the base has area A = pi in².

The height of the can is equal to the sum of the diameters of 4 tennis balls, so h = 8 in.

This makes the volume of the can Axh = 8pi in³.

The volume of the air is then equal to [8pi – (16/3)pi] in³ = ??

Now compare the volume of the tennis balls to the volume of the air.

Surprised?