The ratio of the number of tarts in Container V to the number of tarts in Container W was 9 : 5. 40% of the tarts in Container V and 0.8 of those in Container W were mocha. After transferring the tarts between the 2 boxes, the number of mango tarts in both boxes are the same. Likewise, the number of mocha tarts in both boxes are the same. If a total of 252 tarts were moved, how many more tarts were there in Container V than Container W at first?

Container V		Container W
9 u		5 u
Mocha	Mango	Mocha	Mango
3.6 u	5.4 u	4 u	1 u
+ 0.2 u	- 2.2 u	- 0.2 u	+ 2.2 u
3.8 u	3.2 u	3.8 u	3.2 u

Number of mocha tarts in Container V
= 40% x 9 u
= ⁴⁰₁₀₀ x 9 u
= 3.6 u

Number of mango tarts in Container V
= 9 u - 3.6 u
= 5.4 u

Number of mocha tarts in Container W
= 0.8 x 5 u
= 4 u

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

Number of mocha tarts in each box in the end
= (3.6 u + 4 u) ÷ 2
= 7.6 u ÷ 2
= 3.8 u

Number of mango tarts in each box in the end
= (5.4 u + 1 u) ÷ 2
= 6.4 u ÷ 2
= 3.2 u

Number of tarts moved
= 0.2 u + 2.2 u
= 2.4 u

2.4 u = 252

1 u = 252 ÷ 2.4 = 105

Number of more tarts in Container V than Container W at first
= 9 u - 5 u
= 4 u
= 4 x 105
= 420

Answer(s): 420