Container W contains 3 gold marbles and 4 blue marbles. Container X contains 102 gold marbles and 45 blue marbles. How many blue marbles and gold marbles must be transferred from Container X to put into Container W so that 50% of the marbles in Container A are gold and 70% of the marbles in Container X are gold?

	Container W		Container X
	Gold marbles	Blue marbles	Gold marbles	Blue marbles
Before	3	4	102	45
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	7 p	3 p

50% = ⁵⁰₁₀₀ = 12

70% = ⁷⁰₁₀₀ = 710

Number of gold marbles = 3 + 102 = 105 

Number of blue marbles = 4 + 45 = 49 

1 u + 7 p = 105 --- (1)

1 u + 3 p = 49 ---(2)

(1) - (2)
(1 u + 7 p) - (1 u + 3 p) = 105 - 49
7 p - 3 p = 56
4 p = 56

1 p = 56 ÷ 4 = 14

From (2):
1 u + 3 p = 49
1 u + 3 x 14 = 49
1 u + 42 = 49

1 u = 49 - 42 = 7

Number of blue marbles to be transferred from Container X to Container W
= 45 - 3 p
= 45 - 3 x 14
= 45 - 42
= 3

Number of gold marbles to be transferred from Container X to Container W
= 1 u - 3
= 7 - 3
= 4

Total number of blue and gold marbles to be transferred from Container X to Container W
= 3 + 4
= 7

Answer(s): 7