The ratio of the number of wafers in Container K to the number of wafers in Container L was 7 : 3. 20% of the wafers in Container K and 0.8 of those in Container L were chocolate. After transferring the wafers between the 2 containers, the number of peach wafers in both containers are the same. Likewise, the number of chocolate wafers in both containers are the same. If a total of 156 wafers were moved, how many more wafers were there in Container K than Container L at first?

Container K		Container L
7 u		3 u
Chocolate	Peach	Chocolate	Peach
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 chocolate wafers in Container K
= 20% x 7 u
= ²⁰₁₀₀ x 7 u
= 1.4 u

Number of peach wafers in Container K
= 7 u - 1.4 u
= 5.6 u

Number of chocolate wafers in Container L
= 0.8 x 3 u
= 2.4 u

Number of peach wafers in Container L
= 3 u - 2.4 u
= 0.6 u

Number of chocolate wafers in each container in the end
= (1.4 u + 2.4 u) ÷ 2
= 3.8 u ÷ 2
= 1.9 u

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

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

3 u = 156

1 u = 156 ÷ 3 = 52

Number of more wafers in Container K than Container L at first
= 7 u - 3 u
= 4 u
= 4 x 52
= 208

Answer(s): 208