At a grocery store, bannanas cost .90 each and oranges cost .80 each. Ava has 15 dollars to spend. If Ava wants to buy exactly 5 bannanas, at most how many oranges can she buy

She can buy at most 13 oranges because 5 times .90 is 4.50 and 15-4.5 is 10.50 and 10.50 divided by .80 is 13.125 so she can buy 13 oranges.