The ratio of the number of cupcakes in Container C to the number of cupcakes in Container D was 7 : 3. 20% of the cupcakes in Container C and 0.8 of those in Container D were butter cream. After transferring the cupcakes between the 2 containers, the number of cherry cupcakes in both containers are the same. Likewise, the number of butter cream cupcakes in both containers are the same. If a total of 240 cupcakes were moved, how many more cupcakes were there in Container C than Container D at first?

Container C		Container D
7 u		3 u
Butter Cream	Cherry	Butter Cream	Cherry
1.4 u	5.6 u	2.4 u	0.6 u
+ 0.5 u	- 2.5 u	- 0.5 u	+ 2.5 u
1.9 u	3.1 u	1.9 u	3.1 u

Number of butter cream cupcakes in Container C
= 20% x 7 u
= ²⁰₁₀₀ x 7 u
= 1.4 u

Number of cherry cupcakes in Container C
= 7 u - 1.4 u
= 5.6 u

Number of butter cream cupcakes in Container D
= 0.8 x 3 u
= 2.4 u

Number of cherry cupcakes in Container D
= 3 u - 2.4 u
= 0.6 u

Number of butter cream cupcakes in each container in the end
= (1.4 u + 2.4 u) ÷ 2
= 3.8 u ÷ 2
= 1.9 u

Number of cherry cupcakes in each container in the end
= (5.6 u + 0.6 u) ÷ 2
= 6.2 u ÷ 2
= 3.1 u

Number of cupcakes moved
= 0.5 u + 2.5 u
= 3 u

3 u = 240

1 u = 240 ÷ 3 = 80

Number of more cupcakes in Container C than Container D at first
= 7 u - 3 u
= 4 u
= 4 x 80
= 320

Answer(s): 320