Tiffany baked 30 cupcakes. ³₅ of the cupcakes were vanilla cupcakes. The rest were peach cupcakes. She gave an equal number of vanilla cupcakes and peach cupcakes away and had 3 times as many vanilla cupcakes as peach cupcakes left. How many cupcakes did she give away?

	Vanilla cupcakes	Peach 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 Tiffany gave away an equal number of vanilla cupcakes and peach cupcakes, the difference in the number of vanilla cupcakes and peach cupcakes remains unchanged.  Make the difference in the vanilla cupcakes and peach cupcakes the same.  LCM of 1 and 2 is 2.

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

10 u = 30

1 u = 30 ÷ 10 = 3

Number of cupcakes that Tiffany gave away
= 3 u + 3 u
= 6 u
= 6 x 3 
= 18

Answer(s): 18