Roshel baked 90 cupcakes. ³₅ of the cupcakes were strawberry cupcakes. The rest were butter cream cupcakes. She gave an equal number of strawberry cupcakes and butter cream cupcakes away and had 3 times as many strawberry cupcakes as butter cream cupcakes left. How many cupcakes did she give away?

	Strawberry cupcakes	Butter cream cupcakes	Difference
Before	3x2 = 6 u	2x2 = 4 u	1x2 = 2 u
Change	- 3 u	- 3 u
After	3x1 = 3 u	1x1 = 1 u	2x1 = 2 u

Since Roshel gave away an equal number of strawberry cupcakes and butter cream cupcakes, the difference in the number of strawberry cupcakes and butter cream cupcakes remains unchanged.  Make the difference in the strawberry cupcakes and butter cream cupcakes the same.  LCM of 1 and 2 is 2.

Total number of cupcakes at first
= 6 u + 4 u
= 10 u

10 u = 90

1 u = 90 ÷ 10 = 9

Number of cupcakes that Roshel gave away
= 3 u + 3 u
= 6 u
= 6 x 9 
= 54

Answer(s): 54