Opal made 396 more blueberry wafers than cheese wafers. After she gave away ⁵₇ of the blueberry wafers and ¹₈ of the cheese wafers, there were an equal number of blueberry wafers and cheese wafers left. How many blueberry wafers did she give away?

	Blueberry wafers	Cheese wafers	Difference
Before	7x7 = 49 u	8x2 = 16 u	33 u
Change	- 5x7 = - 35 u	- 1x2 = - 2 u
After	2x7 = 14 u	7x2 = 14 u

Fraction of blueberry wafers left
= 1 - ⁵₇
= ²₇

Fraction of cheese wafers left
= 1 - ¹₈
= ⁷₈

The number of blueberry wafers and cheese wafers in the end is the same. Make the numerators the same.  LCM of 7 and 2 is 14.

²₇ of blueberry wafers = ⁷₈ of cheese wafers
¹⁴₄₉ of blueberry wafers = ¹⁴₁₆ of cheese wafers

Number of more blueberry wafers than cheese wafers at first
= 49 u - 16 u
= 33 u

33 u = 396

1 u = 396 ÷ 33 = 12

Number of blueberry wafers that Opal gave away
= 49 u - 14 u
= 35 u
= 35 x 12
= 420

Answer(s): 420