Container M contains 16 red marbles and 9 brown marbles. Container N contains 49 red marbles and 26 brown marbles. How many brown marbles and red marbles must be removed from Container N to put into Container M so that 50% of the marbles in Container A are red and 75% of the marbles in Container N are red?

	Container M		Container N
	Red marbles	Brown marbles	Red marbles	Brown marbles
Before	16	9	49	26
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of red marbles = 16 + 49 = 65 

Number of brown marbles = 9 + 26 = 35 

1 u + 3 p = 65 --- (1)

1 u + 1 p = 35 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 65 - 35
3 p - 1 p = 30
2 p = 30

1 p = 30 ÷ 2 = 15

From (2):
1 u + 1 p = 35
1 u + 1 x 15 = 35
1 u + 15 = 35

1 u = 35 - 15 = 20

Number of brown marbles to be removed from Container N to Container M
= 26 - 1 p
= 26 - 1 x 15
= 26 - 15
= 11

Number of red marbles to be removed from Container N to Container M
= 1 u - 16
= 20 - 16
= 4

Total number of brown and red marbles to be removed from Container N to Container M
= 11 + 4
= 15

Answer(s): 15