The ratio of the number of puffs in Container K to the number of puffs in Container L was 7 : 5. 10% of the puffs in Container K and 0.7 of those in Container L were strawberry. After transferring the puffs between the 2 boxes, the number of matcha puffs in both boxes are the same. Likewise, the number of strawberry puffs in both boxes are the same. If a total of 247 puffs were moved, how many more puffs were there in Container K than Container L at first?

Container K		Container L
7 u		5 u
Strawberry	Matcha	Strawberry	Matcha
0.7 u	6.3 u	3.5 u	1.5 u
+ 1.4 u	- 2.4 u	- 1.4 u	+ 2.4 u
2.1 u	3.9 u	2.1 u	3.9 u

Number of strawberry puffs in Container K
= 10% x 7 u
= ¹⁰₁₀₀ x 7 u
= 0.7 u

Number of matcha puffs in Container K
= 7 u - 0.7 u
= 6.3 u

Number of strawberry puffs in Container L
= 0.7 x 5 u
= 3.5 u

Number of matcha puffs in Container L
= 5 u - 3.5 u
= 1.5 u

Number of strawberry puffs in each box in the end
= (0.7 u + 3.5 u) ÷ 2
= 4.2 u ÷ 2
= 2.1 u

Number of matcha puffs in each box in the end
= (6.3 u + 1.5 u) ÷ 2
= 7.8 u ÷ 2
= 3.9 u

Number of puffs moved
= 1.4 u + 2.4 u
= 3.8 u

3.8 u = 247

1 u = 247 ÷ 3.8 = 65

Number of more puffs in Container K than Container L at first
= 7 u - 5 u
= 2 u
= 2 x 65
= 130

Answer(s): 130