The price of an apple is one third that of an orange. Robert paid $10.80 for 5 oranges and 12 apples.

(a) How many apples could he buy for $10.80?

(b) How much does one apple cost?

a: 27 apples

b: $0.40 apples

Step-by-step explanation:

a: another way of saying that the price of an apple one-third that of an orange is that you can get 3 apples for the price of 1 orange. If he bought 5 oranges, he could have gotten 15 apples, so 27 apples total.

b: $10.80/27 = $0.40 per apple