divide 15 by 3 then multiply that number by 5.
15/3=5
5 x 5 = 25 apple pies.
think of it like this:
How many small groups of [3 blueberry pies] was in the group of 15. the answer is 5. so if the baker makes 5 for every three, and there are 5 threes, then there will be 25 apple pies. because 5 times 5 is 25.