The ratio of the number of cookies in Container Y to the number of cookies in Container Z was 5 : 3. 40% of the cookies in Container Y and 0.8 of those in Container Z were chocolate. After transferring the cookies between the 2 containers, the number of peach cookies in both containers are the same. Likewise, the number of chocolate cookies in both containers are the same. If a total of 231 cookies were moved, how many more cookies were there in Container Y than Container Z at first?

Container Y		Container Z
5 u		3 u
Chocolate	Peach	Chocolate	Peach
2 u	3 u	2.4 u	0.6 u
+ 0.2 u	- 1.2 u	- 0.2 u	+ 1.2 u
2.2 u	1.8 u	2.2 u	1.8 u

Number of chocolate cookies in Container Y
= 40% x 5 u
= ⁴⁰₁₀₀ x 5 u
= 2 u

Number of peach cookies in Container Y
= 5 u - 2 u
= 3 u

Number of chocolate cookies in Container Z
= 0.8 x 3 u
= 2.4 u

Number of peach cookies in Container Z
= 3 u - 2.4 u
= 0.6 u

Number of chocolate cookies in each container in the end
= (2 u + 2.4 u) ÷ 2
= 4.4 u ÷ 2
= 2.2 u

Number of peach cookies in each container in the end
= (3 u + 0.6 u) ÷ 2
= 3.6 u ÷ 2
= 1.8 u

Number of cookies moved
= 0.2 u + 1.2 u
= 1.4 u

1.4 u = 231

1 u = 231 ÷ 1.4 = 165

Number of more cookies in Container Y than Container Z at first
= 5 u - 3 u
= 2 u
= 2 x 165
= 330

Answer(s): 330