Box P contains 4 pink marbles and 5 green marbles. Box Q contains 149 pink marbles and 68 green marbles. How many green marbles and pink marbles must be transferred from Box Q to put into Box P so that 50% of the marbles in Box A are pink and 70% of the marbles in Box Q are pink?

	Box P		Box Q
	Pink marbles	Green marbles	Pink marbles	Green marbles
Before	4	5	149	68
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	7 p	3 p

50% = ⁵⁰₁₀₀ = 12

70% = ⁷⁰₁₀₀ = 710

Number of pink marbles = 4 + 149 = 153 

Number of green marbles = 5 + 68 = 73 

1 u + 7 p = 153 --- (1)

1 u + 3 p = 73 ---(2)

(1) - (2)
(1 u + 7 p) - (1 u + 3 p) = 153 - 73
7 p - 3 p = 80
4 p = 80

1 p = 80 ÷ 4 = 20

From (2):
1 u + 3 p = 73
1 u + 3 x 20 = 73
1 u + 60 = 73

1 u = 73 - 60 = 13

Number of green marbles to be transferred from Box Q to Box P
= 68 - 3 p
= 68 - 3 x 20
= 68 - 60
= 8

Number of pink marbles to be transferred from Box Q to Box P
= 1 u - 4
= 13 - 4
= 9

Total number of green and pink marbles to be transferred from Box Q to Box P
= 8 + 9
= 17

Answer(s): 17