Container L contains 8 red marbles and 5 white marbles. Container M contains 43 red marbles and 20 white marbles. How many white marbles and red marbles must be transferred from Container M to put into Container L so that 50% of the marbles in Container A are red and 75% of the marbles in Container M are red?

	Container L		Container M
	Red marbles	White marbles	Red marbles	White marbles
Before	8	5	43	20
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of red marbles = 8 + 43 = 51 

Number of white marbles = 5 + 20 = 25 

1 u + 3 p = 51 --- (1)

1 u + 1 p = 25 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 51 - 25
3 p - 1 p = 26
2 p = 26

1 p = 26 ÷ 2 = 13

From (2):
1 u + 1 p = 25
1 u + 1 x 13 = 25
1 u + 13 = 25

1 u = 25 - 13 = 12

Number of white marbles to be transferred from Container M to Container L
= 20 - 1 p
= 20 - 1 x 13
= 20 - 13
= 7

Number of red marbles to be transferred from Container M to Container L
= 1 u - 8
= 12 - 8
= 4

Total number of white and red marbles to be transferred from Container M to Container L
= 7 + 4
= 11

Answer(s): 11