If 137 green stickers are added, 30% of the stickers will be blue stickers.
If 177 blue stickers are added, 20% of the stickers will be green stickers.

1. How many green stickers are there? 
2. How many blue stickers are there? 

	Scenario 1		Scenario 2
	Green	Blue	Green	Blue
Before	7 u - 137	3 u	1 p	4 p - 177
Change	+ 137	No change	No change	+ 177
After	7 u	3 u	1 p	4 p

(a)
30% = ³⁰₁₀₀ = ³₁₀
20% = ²⁰₁₀₀ = ¹₅

Scenario 1
Fraction of the stickers that are green
= 1 - ³₁₀
= ⁷₁₀

Number of green stickers at first = 7 u - 137
Number of blue stickers at first = 3 u

Scenario 2
Fraction of the stickers that are blue
= 1 - ¹₅
= ⁴₅

Number of green stickers at first = 1 p
Number of blue stickers at first = 4 p - 177

7 u - 137 = 1 p --- (1)

3 u = 4 p - 177
3 u + 177 = 4 p --- (2)

(1) _{x 4}
28 u - 548 = 4 p --- (3)

(3) = (2)
28 u - 548 = 3 u + 177
28 u - 3 u = 548 + 177
25 u = 725

1 u = 725 ÷ 25 = 29

Number of green stickers
= 7 u - 137
= 7 x 29 - 137
= 203 - 137
= 66

(b)
Number of blue stickers
= 3 u
= 3 x 29
= 87

Answer(s): (a) 66; (b) 87