Container C contains 3 yellow balls and 8 silver balls. Container D contains 24 yellow balls and 13 silver balls. How many silver balls and yellow balls must be removed from Container D to put into Container C so that 50% of the balls in Container A are yellow and 75% of the balls in Container D are yellow?

	Container C		Container D
	Yellow balls	Silver balls	Yellow balls	Silver balls
Before	3	8	24	13
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of yellow balls = 3 + 24 = 27 

Number of silver balls = 8 + 13 = 21 

1 u + 3 p = 27 --- (1)

1 u + 1 p = 21 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 27 - 21
3 p - 1 p = 6
2 p = 6

1 p = 6 ÷ 2 = 3

From (2):
1 u + 1 p = 21
1 u + 1 x 3 = 21
1 u + 3 = 21

1 u = 21 - 3 = 18

Number of silver balls to be removed from Container D to Container C
= 13 - 1 p
= 13 - 1 x 3
= 13 - 3
= 10

Number of yellow balls to be removed from Container D to Container C
= 1 u - 3
= 18 - 3
= 15

Total number of silver and yellow balls to be removed from Container D to Container C
= 10 + 15
= 25

Answer(s): 25