Box T contains 13 green marbles and 6 white marbles. Box U contains 88 green marbles and 47 white marbles. How many white marbles and green marbles must be transferred from Box U to put into Box T so that 50% of the marbles in Box A are green and 70% of the marbles in Box U are green?

	Box T		Box U
	Green marbles	White marbles	Green marbles	White marbles
Before	13	6	88	47
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	7 p	3 p

50% = ⁵⁰₁₀₀ = 12

70% = ⁷⁰₁₀₀ = 710

Number of green marbles = 13 + 88 = 101 

Number of white marbles = 6 + 47 = 53 

1 u + 7 p = 101 --- (1)

1 u + 3 p = 53 ---(2)

(1) - (2)
(1 u + 7 p) - (1 u + 3 p) = 101 - 53
7 p - 3 p = 48
4 p = 48

1 p = 48 ÷ 4 = 12

From (2):
1 u + 3 p = 53
1 u + 3 x 12 = 53
1 u + 36 = 53

1 u = 53 - 36 = 17

Number of white marbles to be transferred from Box U to Box T
= 47 - 3 p
= 47 - 3 x 12
= 47 - 36
= 11

Number of green marbles to be transferred from Box U to Box T
= 1 u - 13
= 17 - 13
= 4

Total number of white and green marbles to be transferred from Box U to Box T
= 11 + 4
= 15

Answer(s): 15