Box N contains 8 grey beads and 11 white beads. Box P contains 75 grey beads and 24 white beads. How many white beads and grey beads must be removed from Box P to put into Box N so that 50% of the beads in Box A are grey and 80% of the beads in Box P are grey?

	Box N		Box P
	Grey beads	White beads	Grey beads	White beads
Before	8	11	75	24
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	4 p	1 p

50% = ⁵⁰₁₀₀ = 12

80% = ⁸⁰₁₀₀ = 45

Number of grey beads = 8 + 75 = 83 

Number of white beads = 11 + 24 = 35 

1 u + 4 p = 83 --- (1)

1 u + 1 p = 35 ---(2)

(1) - (2)
(1 u + 4 p) - (1 u + 1 p) = 83 - 35
4 p - 1 p = 48
3 p = 48

1 p = 48 ÷ 3 = 16

From (2):
1 u + 1 p = 35
1 u + 1 x 16 = 35
1 u + 16 = 35

1 u = 35 - 16 = 19

Number of white beads to be removed from Box P to Box N
= 24 - 1 p
= 24 - 1 x 16
= 24 - 16
= 8

Number of grey beads to be removed from Box P to Box N
= 1 u - 8
= 19 - 8
= 11

Total number of white and grey beads to be removed from Box P to Box N
= 8 + 11
= 19

Answer(s): 19