Alice and Bob shared a pizza with 12 equally-sized slices. Alice wanted a plain pizza, but Bob wanted pepperoni on half of the pizza. The cost of a plain pizza was $12, and there was an additional cost of $3 for putting pepperoni on one half. Bob ate all of the slices of pepperoni pizza and two plain slices. Alice ate the remainder. Each then paid for what he or she had eaten. How many more dollars did Bob pay than Alice?
5
6
7
8
9
