Container T contains 9 white marbles and 8 pink marbles. Container U contains 78 white marbles and 25 pink marbles. How many pink marbles and white marbles must be moved from Container U to put into Container T so that 50% of the marbles in Container A are white and 80% of the marbles in Container U are white?

	Container T		Container U
	White marbles	Pink marbles	White marbles	Pink marbles
Before	9	8	78	25
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	4 p	1 p

50% = ⁵⁰₁₀₀ = 12

80% = ⁸⁰₁₀₀ = 45

Number of white marbles = 9 + 78 = 87 

Number of pink marbles = 8 + 25 = 33 

1 u + 4 p = 87 --- (1)

1 u + 1 p = 33 ---(2)

(1) - (2)
(1 u + 4 p) - (1 u + 1 p) = 87 - 33
4 p - 1 p = 54
3 p = 54

1 p = 54 ÷ 3 = 18

From (2):
1 u + 1 p = 33
1 u + 1 x 18 = 33
1 u + 18 = 33

1 u = 33 - 18 = 15

Number of pink marbles to be moved from Container U to Container T
= 25 - 1 p
= 25 - 1 x 18
= 25 - 18
= 7

Number of white marbles to be moved from Container U to Container T
= 1 u - 9
= 15 - 9
= 6

Total number of pink and white marbles to be moved from Container U to Container T
= 7 + 6
= 13

Answer(s): 13