The ratio of the number of puffs in Container P to the number of puffs in Container Q was 7 : 5. 20% of the puffs in Container P and 0.7 of those in Container Q were cherry. After transferring the puffs between the 2 containers, the number of vanilla puffs in both containers are the same. Likewise, the number of cherry puffs in both containers are the same. If a total of 186 puffs were moved, how many more puffs were there in Container P than Container Q at first?

Container P		Container Q
7 u		5 u
Cherry	Vanilla	Cherry	Vanilla
1.4 u	5.6 u	3.5 u	1.5 u
+ 1.05 u	- 2.05 u	- 1.05 u	+ 2.05 u
2.45 u	3.55 u	2.45 u	3.55 u

Number of cherry puffs in Container P
= 20% x 7 u
= ²⁰₁₀₀ x 7 u
= 1.4 u

Number of vanilla puffs in Container P
= 7 u - 1.4 u
= 5.6 u

Number of cherry puffs in Container Q
= 0.7 x 5 u
= 3.5 u

Number of vanilla puffs in Container Q
= 5 u - 3.5 u
= 1.5 u

Number of cherry puffs in each container in the end
= (1.4 u + 3.5 u) ÷ 2
= 4.9 u ÷ 2
= 2.45 u

Number of vanilla puffs in each container in the end
= (5.6 u + 1.5 u) ÷ 2
= 7.1 u ÷ 2
= 3.55 u

Number of puffs moved
= 1.05 u + 2.05 u
= 3.1 u

3.1 u = 186

1 u = 186 ÷ 3.1 = 60

Number of more puffs in Container P than Container Q at first
= 7 u - 5 u
= 2 u
= 2 x 60
= 120

Answer(s): 120