Box M contains 16 gold balls and 9 white balls. Box N contains 43 gold balls and 24 white balls. How many white balls and gold balls must be removed from Box N to put into Box M so that 50% of the balls in Box A are gold and 75% of the balls in Box N are gold?

	Box M		Box N
	Gold balls	White balls	Gold balls	White balls
Before	16	9	43	24
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of gold balls = 16 + 43 = 59 

Number of white balls = 9 + 24 = 33 

1 u + 3 p = 59 --- (1)

1 u + 1 p = 33 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 59 - 33
3 p - 1 p = 26
2 p = 26

1 p = 26 ÷ 2 = 13

From (2):
1 u + 1 p = 33
1 u + 1 x 13 = 33
1 u + 13 = 33

1 u = 33 - 13 = 20

Number of white balls to be removed from Box N to Box M
= 24 - 1 p
= 24 - 1 x 13
= 24 - 13
= 11

Number of gold balls to be removed from Box N to Box M
= 1 u - 16
= 20 - 16
= 4

Total number of white and gold balls to be removed from Box N to Box M
= 11 + 4
= 15

Answer(s): 15