Container M contains 9 purple balls and 2 silver balls. Container N contains 37 purple balls and 26 silver balls. How many silver balls and purple balls must be transferred from Container N to put into Container M so that 50% of the balls in Container A are purple and 75% of the balls in Container N are purple?

	Container M		Container N
	Purple balls	Silver balls	Purple balls	Silver balls
Before	9	2	37	26
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of purple balls = 9 + 37 = 46 

Number of silver balls = 2 + 26 = 28 

1 u + 3 p = 46 --- (1)

1 u + 1 p = 28 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 46 - 28
3 p - 1 p = 18
2 p = 18

1 p = 18 ÷ 2 = 9

From (2):
1 u + 1 p = 28
1 u + 1 x 9 = 28
1 u + 9 = 28

1 u = 28 - 9 = 19

Number of silver balls to be transferred from Container N to Container M
= 26 - 1 p
= 26 - 1 x 9
= 26 - 9
= 17

Number of purple balls to be transferred from Container N to Container M
= 1 u - 9
= 19 - 9
= 10

Total number of silver and purple balls to be transferred from Container N to Container M
= 17 + 10
= 27

Answer(s): 27