Gillian made 51 more cheese biscuits than strawberry biscuits. After she gave away ⁴₇ of the cheese biscuits and ¹₆ of the strawberry biscuits, there were an equal number of cheese biscuits and strawberry biscuits left. How many cheese biscuits did she give away?

	Cheese biscuits	Strawberry biscuits	Difference
Before	7x5 = 35 u	6x3 = 18 u	17 u
Change	- 4x5 = - 20 u	- 1x3 = - 3 u
After	3x5 = 15 u	5x3 = 15 u

Fraction of cheese biscuits left
= 1 - ⁴₇
= ³₇

Fraction of strawberry biscuits left
= 1 - ¹₆
= ⁵₆

The number of cheese biscuits and strawberry biscuits in the end is the same. Make the numerators the same.  LCM of 5 and 3 is 15.

³₇ of cheese biscuits = ⁵₆ of strawberry biscuits
¹⁵₃₅ of cheese biscuits = ¹⁵₁₈ of strawberry biscuits

Number of more cheese biscuits than strawberry biscuits at first
= 35 u - 18 u
= 17 u

17 u = 51

1 u = 51 ÷ 17 = 3

Number of cheese biscuits that Gillian gave away
= 35 u - 15 u
= 20 u
= 20 x 3
= 60

Answer(s): 60