The Jolly Quiz Master serves two sizes of pizza, namely six inch and ten inch. The sizes referring to the diameter of the pizzas, as is the norm. And very tasty they are too.

The other evening they were evidently selling well, and towards the end of food service a customer ordered a ten inch Pizza Margherita. Shortly afterwards the waiter arrived with two six inch Pizza Margheritas. "We have run out of ten inch Pizza Margheritas and so we have given you two six inch Pizza Margheritas for the same price".

The customer took and ate the two pizzas without complaint, clearly feeling that they had got a good deal. But had they?

Did the customer receive a bargain, and why?

Pizzas are circular, and the area of a circle is π r squared, so . . .

A ten inch pizza has an area of 5 x 5 x π or 25π. A six inch pizza has an area of 3 x 3 x π or 9π and two of them have a total area of 18π. Two six inch pizzas give you less pizza than one ten inch pizza.

In fact, to get a bargain you would need three six inch pizzas!