There were some pink stamps and red stamps. The stamps were packed into 2 bags. At first, Packet F contained 145 stamps and 40% of them were red stamps. Packet G contained 205 stamps and 60% of them were red stamps. How many pink stamps and red stamps in total must be moved from Packet F to Packet G such that 20% of the stamps in Packet F are pink and 50% of the stamps in Packet G are red?

	Packet F		Packet G
Total	145		205
	Red stamps	Pink stamps	Red stamps	Pink stamps
Before	58	87	123	82
Change	- ?	- ?	+ ?	+ ?
After	4 u	1 u	1 p	1 p

Number of red stamps in Packet F at first
= 40% x 145
= ⁴⁰₁₀₀ x 145
= 58

Number of pink stamps in Packet F at first
= 145 - 58
= 87

Number of red stamps in Packet G at first
= 60% x 205
= ⁶⁰₁₀₀ x 205
= 123

Number of pink stamps in Packet G at first
= 205 - 123
= 82

Packet F in the end
20% = ²⁰₁₀₀ =¹₅
Red stamps : Pink stamps = 4 : 1

Packet G in the end
50% = ⁵⁰₁₀₀ =¹₂
Red stamps : Pink stamps = 1 : 1

Total number of red stamps = 4 u + 1 p

4 u + 1 p = 58 + 123
4 u + 1 p = 181 

1 p = 181 - 4 u --- (1)

Total number of pink stamps = 1 u + 1 p
1 u + 1 p = 87 + 82
1 u + 1 p = 169

1 p = 169 - 1 u --- (2)

(2) = (1)
169 - 1 u = 181 - 4 u
4 u - 1 u = 181 - 169
3 u = 12

1 u = 12 ÷ 3 = 4

Total number of pink stamps and red stamps that must be moved from Packet F to Packet G
= 145 - 5 u
= 145 - 5 x 4
= 145 - 20
= 125

Answer(s): 125