The ratio of the number of tarts in Container T to the number of tarts in Container U was 7 : 3. 20% of the tarts in Container T and 0.6 of those in Container U were cherry. After transferring the tarts between the 2 boxes, the number of chocolate tarts in both boxes are the same. Likewise, the number of cherry tarts in both boxes are the same. If a total of 168 tarts were moved, how many more tarts were there in Container T than Container U at first?

Container T		Container U
7 u		3 u
Cherry	Chocolate	Cherry	Chocolate
1.4 u	5.6 u	1.8 u	1.2 u
+ 0.2 u	- 2.2 u	- 0.2 u	+ 2.2 u
1.6 u	3.4 u	1.6 u	3.4 u

Number of cherry tarts in Container T
= 20% x 7 u
= ²⁰₁₀₀ x 7 u
= 1.4 u

Number of chocolate tarts in Container T
= 7 u - 1.4 u
= 5.6 u

Number of cherry tarts in Container U
= 0.6 x 3 u
= 1.8 u

Number of chocolate tarts in Container U
= 3 u - 1.8 u
= 1.2 u

Number of cherry tarts in each box in the end
= (1.4 u + 1.8 u) ÷ 2
= 3.2 u ÷ 2
= 1.6 u

Number of chocolate tarts in each box in the end
= (5.6 u + 1.2 u) ÷ 2
= 6.8 u ÷ 2
= 3.4 u

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

2.4 u = 168

1 u = 168 ÷ 2.4 = 70

Number of more tarts in Container T than Container U at first
= 7 u - 3 u
= 4 u
= 4 x 70
= 280

Answer(s): 280