Box T contains 4 brown beads and 9 silver beads. Box U contains 57 brown beads and 16 silver beads. How many silver beads and brown beads must be removed from Box U to put into Box T so that 50% of the beads in Box A are brown and 80% of the beads in Box U are brown?

	Box T		Box U
	Brown beads	Silver beads	Brown beads	Silver beads
Before	4	9	57	16
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	4 p	1 p

50% = ⁵⁰₁₀₀ = 12

80% = ⁸⁰₁₀₀ = 45

Number of brown beads = 4 + 57 = 61 

Number of silver beads = 9 + 16 = 25 

1 u + 4 p = 61 --- (1)

1 u + 1 p = 25 ---(2)

(1) - (2)
(1 u + 4 p) - (1 u + 1 p) = 61 - 25
4 p - 1 p = 36
3 p = 36

1 p = 36 ÷ 3 = 12

From (2):
1 u + 1 p = 25
1 u + 1 x 12 = 25
1 u + 12 = 25

1 u = 25 - 12 = 13

Number of silver beads to be removed from Box U to Box T
= 16 - 1 p
= 16 - 1 x 12
= 16 - 12
= 4

Number of brown beads to be removed from Box U to Box T
= 1 u - 4
= 13 - 4
= 9

Total number of silver and brown beads to be removed from Box U to Box T
= 4 + 9
= 13

Answer(s): 13