Container E contains 14 grey marbles and 11 green marbles. Container F contains 37 grey marbles and 18 green marbles. How many green marbles and grey marbles must be moved from Container F to put into Container E so that 50% of the marbles in Container A are grey and 75% of the marbles in Container F are grey?

	Container E		Container F
	Grey marbles	Green marbles	Grey marbles	Green marbles
Before	14	11	37	18
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	3 p	1 p

50% = ⁵⁰₁₀₀ = 12

75% = ⁷⁵₁₀₀ = 34

Number of grey marbles = 14 + 37 = 51 

Number of green marbles = 11 + 18 = 29 

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

1 u + 1 p = 29 ---(2)

(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 51 - 29
3 p - 1 p = 22
2 p = 22

1 p = 22 ÷ 2 = 11

From (2):
1 u + 1 p = 29
1 u + 1 x 11 = 29
1 u + 11 = 29

1 u = 29 - 11 = 18

Number of green marbles to be moved from Container F to Container E
= 18 - 1 p
= 18 - 1 x 11
= 18 - 11
= 7

Number of grey marbles to be moved from Container F to Container E
= 1 u - 14
= 18 - 14
= 4

Total number of green and grey marbles to be moved from Container F to Container E
= 7 + 4
= 11

Answer(s): 11