Emily made 20 more banana biscuits than mocca biscuits. After she gave away ²₅ of the banana biscuits and ¹₅ of the mocca biscuits, there were an equal number of banana biscuits and mocca biscuits left. How many banana biscuits did she give away?

	Banana biscuits	Mocca biscuits	Difference
Before	5x4 = 20 u	5x3 = 15 u	5 u
Change	- 2x4 = - 8 u	- 1x3 = - 3 u
After	3x4 = 12 u	4x3 = 12 u

Fraction of banana biscuits left
= 1 - ²₅
= ³₅

Fraction of mocca biscuits left
= 1 - ¹₅
= ⁴₅

The number of banana biscuits and mocca biscuits in the end is the same. Make the numerators the same.  LCM of 4 and 3 is 12.

³₅ of banana biscuits = ⁴₅ of mocca biscuits
¹²₂₀ of banana biscuits = ¹²₁₅ of mocca biscuits

Number of more banana biscuits than mocca biscuits at first
= 20 u - 15 u
= 5 u

5 u = 20

1 u = 20 ÷ 5 = 4

Number of banana biscuits that Emily gave away
= 20 u - 12 u
= 8 u
= 8 x 4
= 32

Answer(s): 32