There were some yellow stickers and red stickers. The stickers were packed into 2 bags. At first, Packet B contained 150 stickers and 40% of them were red stickers. Packet C contained 190 stickers and 60% of them were red stickers. How many yellow stickers and red stickers in total must be moved from Packet B to Packet C such that 30% of the stickers in Packet B are yellow and 50% of the stickers in Packet C are red?

	Packet B		Packet C
Total	150		190
	Red stickers	Yellow stickers	Red stickers	Yellow stickers
Before	60	90	114	76
Change	- ?	- ?	+ ?	+ ?
After	7 u	3 u	1 p	1 p

Number of red stickers in Packet B at first
= 40% x 150
= ⁴⁰₁₀₀ x 150
= 60

Number of yellow stickers in Packet B at first
= 150 - 60
= 90

Number of red stickers in Packet C at first
= 60% x 190
= ⁶⁰₁₀₀ x 190
= 114

Number of yellow stickers in Packet C at first
= 190 - 114
= 76

Packet B in the end
30% = ³⁰₁₀₀ =³₁₀
Red stickers : Yellow stickers = 7 : 3

Packet C in the end
50% = ⁵⁰₁₀₀ =¹₂
Red stickers : Yellow stickers = 1 : 1

Total number of red stickers = 7 u + 1 p

7 u + 1 p = 60 + 114
7 u + 1 p = 174 

1 p = 174 - 7 u --- (1)

Total number of yellow stickers = 3 u + 1 p
3 u + 1 p = 90 + 76
3 u + 1 p = 166

1 p = 166 - 3 u --- (2)

(2) = (1)
166 - 3 u = 174 - 7 u
7 u - 3 u = 174 - 166
4 u = 8

1 u = 8 ÷ 4 = 2

Total number of yellow stickers and red stickers that must be moved from Packet B to Packet C
= 150 - 10 u
= 150 - 10 x 2
= 150 - 20
= 130

Answer(s): 130