The ratio of the number of biscuits in Container B to the number of biscuits in Container C was 7 : 5. 40% of the biscuits in Container B and 0.8 of those in Container C were mocha. After transferring the biscuits between the 2 containers, the number of vanilla biscuits in both containers are the same. Likewise, the number of mocha biscuits in both containers are the same. If a total of 297 biscuits were moved, how many more biscuits were there in Container B than Container C at first?

Container B		Container C
7 u		5 u
Mocha	Vanilla	Mocha	Vanilla
2.8 u	4.2 u	4 u	1 u
+ 0.6 u	- 1.6 u	- 0.6 u	+ 1.6 u
3.4 u	2.6 u	3.4 u	2.6 u

Number of mocha biscuits in Container B
= 40% x 7 u
= ⁴⁰₁₀₀ x 7 u
= 2.8 u

Number of vanilla biscuits in Container B
= 7 u - 2.8 u
= 4.2 u

Number of mocha biscuits in Container C
= 0.8 x 5 u
= 4 u

Number of vanilla biscuits in Container C
= 5 u - 4 u
= 1 u

Number of mocha biscuits in each container in the end
= (2.8 u + 4 u) ÷ 2
= 6.8 u ÷ 2
= 3.4 u

Number of vanilla biscuits in each container in the end
= (4.2 u + 1 u) ÷ 2
= 5.2 u ÷ 2
= 2.6 u

Number of biscuits moved
= 0.6 u + 1.6 u
= 2.2 u

2.2 u = 297

1 u = 297 ÷ 2.2 = 135

Number of more biscuits in Container B than Container C at first
= 7 u - 5 u
= 2 u
= 2 x 135
= 270

Answer(s): 270