The ratio of the number of biscuits in Container R to the number of biscuits in Container S was 9 : 5. 10% of the biscuits in Container R and 0.9 of those in Container S were mocha. After transferring the biscuits between the 2 boxes, the number of chocolate biscuits in both boxes are the same. Likewise, the number of mocha biscuits in both boxes are the same. If a total of 196 biscuits were moved, how many more biscuits were there in Container R than Container S at first?

Container R		Container S
9 u		5 u
Mocha	Chocolate	Mocha	Chocolate
0.9 u	8.1 u	4.5 u	0.5 u
+ 1.8 u	- 3.8 u	- 1.8 u	+ 3.8 u
2.7 u	4.3 u	2.7 u	4.3 u

Number of mocha biscuits in Container R
= 10% x 9 u
= ¹⁰₁₀₀ x 9 u
= 0.9 u

Number of chocolate biscuits in Container R
= 9 u - 0.9 u
= 8.1 u

Number of mocha biscuits in Container S
= 0.9 x 5 u
= 4.5 u

Number of chocolate biscuits in Container S
= 5 u - 4.5 u
= 0.5 u

Number of mocha biscuits in each box in the end
= (0.9 u + 4.5 u) ÷ 2
= 5.4 u ÷ 2
= 2.7 u

Number of chocolate biscuits in each box in the end
= (8.1 u + 0.5 u) ÷ 2
= 8.6 u ÷ 2
= 4.3 u

Number of biscuits moved
= 1.8 u + 3.8 u
= 5.6 u

5.6 u = 196

1 u = 196 ÷ 5.6 = 35

Number of more biscuits in Container R than Container S at first
= 9 u - 5 u
= 4 u
= 4 x 35
= 140

Answer(s): 140