The ratio of the number of tarts in Container X to the number of tarts in Container Y was 7 : 5. 40% of the tarts in Container X and 0.8 of those in Container Y were peach. After transferring the tarts between the 2 boxes, the number of mango tarts in both boxes are the same. Likewise, the number of peach tarts in both boxes are the same. If a total of 220 tarts were moved, how many more tarts were there in Container X than Container Y at first?

Container X		Container Y
7 u		5 u
Peach	Mango	Peach	Mango
2.8 u	4.2 u	4 u	1 u
+ 0.6 u	- 1.6 u	- 0.6 u	+ 1.6 u
3.4 u	2.6 u	3.4 u	2.6 u

Number of peach tarts in Container X
= 40% x 7 u
= ⁴⁰₁₀₀ x 7 u
= 2.8 u

Number of mango tarts in Container X
= 7 u - 2.8 u
= 4.2 u

Number of peach tarts in Container Y
= 0.8 x 5 u
= 4 u

Number of mango tarts in Container Y
= 5 u - 4 u
= 1 u

Number of peach tarts in each box in the end
= (2.8 u + 4 u) ÷ 2
= 6.8 u ÷ 2
= 3.4 u

Number of mango tarts in each box in the end
= (4.2 u + 1 u) ÷ 2
= 5.2 u ÷ 2
= 2.6 u

Number of tarts moved
= 0.6 u + 1.6 u
= 2.2 u

2.2 u = 220

1 u = 220 ÷ 2.2 = 100

Number of more tarts in Container X than Container Y at first
= 7 u - 5 u
= 2 u
= 2 x 100
= 200

Answer(s): 200