Cathy made 63 more blueberry biscuits than banana biscuits. After she gave away ²₇ of the blueberry biscuits and ¹₈ of the banana biscuits, there were an equal number of blueberry biscuits and banana biscuits left. How many blueberry biscuits did she give away?

	Blueberry biscuits	Banana biscuits	Difference
Before	7x7 = 49 u	8x5 = 40 u	9 u
Change	- 2x7 = - 14 u	- 1x5 = - 5 u
After	5x7 = 35 u	7x5 = 35 u

Fraction of blueberry biscuits left
= 1 - ²₇
= ⁵₇

Fraction of banana biscuits left
= 1 - ¹₈
= ⁷₈

The number of blueberry biscuits and banana biscuits in the end is the same. Make the numerators the same.  LCM of 7 and 5 is 35.

⁵₇ of blueberry biscuits = ⁷₈ of banana biscuits
³⁵₄₉ of blueberry biscuits = ³⁵₄₀ of banana biscuits

Number of more blueberry biscuits than banana biscuits at first
= 49 u - 40 u
= 9 u

9 u = 63

1 u = 63 ÷ 9 = 7

Number of blueberry biscuits that Cathy gave away
= 49 u - 35 u
= 14 u
= 14 x 7
= 98

Answer(s): 98