Risa baked 144 biscuits. ⁵₈ of the biscuits were mango biscuits. The rest were strawberry biscuits. She gave an equal number of mango biscuits and strawberry biscuits away and had 4 times as many mango biscuits as strawberry biscuits left. How many biscuits did she give away?

	Mango biscuits	Strawberry biscuits	Difference
Before	5x3 = 15 u	3x3 = 9 u	2x3 = 6 u
Change	- 7 u	- 7 u
After	4x2 = 8 u	1x2 = 2 u	3x2 = 6 u

Since Risa gave away an equal number of mango biscuits and strawberry biscuits, the difference in the number of mango biscuits and strawberry biscuits remains unchanged.  Make the difference in the mango biscuits and strawberry biscuits the same.  LCM of 2 and 3 is 6.

Total number of biscuits at first
= 15 u + 9 u
= 24 u

24 u = 144

1 u = 144 ÷ 24 = 6

Number of biscuits that Risa gave away
= 7 u + 7 u
= 14 u
= 14 x 6 
= 84

Answer(s): 84