Xavier had an equal number of strawberry muffins, blueberry muffins and cream muffins. After he ate 48 strawberry muffins, some blueberry muffins and cream muffins, there were 60 muffins left. The number of blueberry muffins he ate was thrice the number of cream muffins he ate. The number of blueberry muffins left was 21 more than the number of strawberry muffins left. How many strawberry muffins were there at first?

	Strawberry muffins	Blueberry muffins	Cream muffins	Total muffins
Before	1 p + 48	1 p + 3 u + 21	1 p + 3 u + 21
Change	- 48	- 3 u	- 1 u
After	1 p	1 p + 21	1 p + 21 + 1 u	60

Number of blueberry muffins and strawberry muffins was equal at first.

1 p + 3 u + 21 = 1 p + 48
3 u = 48 - 21
3 u = 27

1 u = 27 ÷ 3 = 9

Total number of muffins in the end
= 1 p + 1 p + 21 + 1 p + 21 + 9
= 1 p + 1 p + 1 p + 21 + 21 + 9
= 3 p + 51

3 p + 51 = 60
3 p = 60 - 51
3 p = 9

1 p = 9 ÷ 3 = 3

Number of strawberry muffins at first
= 1 p + 48
= 3 + 48
= 51

Answer(s): 51