Crate C contains 18 brown beads and 16 pink beads. Crate D contains 51 brown beads and 25 pink beads. How many pink beads and brown beads must be removed from Crate D to put into Crate C so that 50% of the beads in Crate A are brown and 70% of the beads in Crate D are brown?

	Crate C		Crate D
	Brown beads	Pink beads	Brown beads	Pink beads
Before	18	16	51	25
Change	+ ?	+ ?	- ?	- ?
After	1 u	1 u	7 p	3 p

50% = ⁵⁰₁₀₀ = 12

70% = ⁷⁰₁₀₀ = 710

Number of brown beads = 18 + 51 = 69 

Number of pink beads = 16 + 25 = 41 

1 u + 7 p = 69 --- (1)

1 u + 3 p = 41 ---(2)

(1) - (2)
(1 u + 7 p) - (1 u + 3 p) = 69 - 41
7 p - 3 p = 28
4 p = 28

1 p = 28 ÷ 4 = 7

From (2):
1 u + 3 p = 41
1 u + 3 x 7 = 41
1 u + 21 = 41

1 u = 41 - 21 = 20

Number of pink beads to be removed from Crate D to Crate C
= 25 - 3 p
= 25 - 3 x 7
= 25 - 21
= 4

Number of brown beads to be removed from Crate D to Crate C
= 1 u - 18
= 20 - 18
= 2

Total number of pink and brown beads to be removed from Crate D to Crate C
= 4 + 2
= 6

Answer(s): 6