There were some pink stickers and purple stickers. The stickers were packed into 2 bags. At first, Box P contained 150 stickers and 30% of them were purple stickers. Box Q contained 144 stickers and 75% of them were purple stickers. How many pink stickers and purple stickers in total must be moved from Box P to Box Q such that 30% of the stickers in Box P are pink and 50% of the stickers in Box Q are purple?

	Box P		Box Q
Total	150		144
	Purple stickers	Pink stickers	Purple stickers	Pink stickers
Before	45	105	108	36
Change	- ?	- ?	+ ?	+ ?
After	7 u	3 u	1 p	1 p

Number of purple stickers in Box P at first
= 30% x 150
= ³⁰₁₀₀ x 150
= 45

Number of pink stickers in Box P at first
= 150 - 45
= 105

Number of purple stickers in Box Q at first
= 75% x 144
= ⁷⁵₁₀₀ x 144
= 108

Number of pink stickers in Box Q at first
= 144 - 108
= 36

Box P in the end
30% = ³⁰₁₀₀ =³₁₀
Purple stickers : Pink stickers = 7 : 3

Box Q in the end
50% = ⁵⁰₁₀₀ =¹₂
Purple stickers : Pink stickers = 1 : 1

Total number of purple stickers = 7 u + 1 p

7 u + 1 p = 45 + 108
7 u + 1 p = 153 

1 p = 153 - 7 u --- (1)

Total number of pink stickers = 3 u + 1 p
3 u + 1 p = 105 + 36
3 u + 1 p = 141

1 p = 141 - 3 u --- (2)

(2) = (1)
141 - 3 u = 153 - 7 u
7 u - 3 u = 153 - 141
4 u = 12

1 u = 12 ÷ 4 = 3

Total number of pink stickers and purple stickers that must be moved from Box P to Box Q
= 150 - 10 u
= 150 - 10 x 3
= 150 - 30
= 120

Answer(s): 120