If 299 blue stickers are added, 30% of the stickers will be green stickers.
If 129 green stickers are added, 10% of the stickers will be blue stickers.

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

	Scenario 1		Scenario 2
	Blue	Green	Blue	Green
Before	7 u - 299	3 u	1 p	9 p - 129
Change	+ 299	No change	No change	+ 129
After	7 u	3 u	1 p	9 p

(a)
30% = ³⁰₁₀₀ = ³₁₀
10% = ¹⁰₁₀₀ = ¹₁₀

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

Number of blue stickers at first = 7 u - 299
Number of green stickers at first = 3 u

Scenario 2
Fraction of the stickers that are green
= 1 - ¹₁₀
= ⁹₁₀

Number of blue stickers at first = 1 p
Number of green stickers at first = 9 p - 129

7 u - 299 = 1 p --- (1)

3 u = 9 p - 129
3 u + 129 = 9 p --- (2)

(1) _{x 9}
63 u - 2691 = 9 p --- (3)

(3) = (2)
63 u - 2691 = 3 u + 129
63 u - 3 u = 2691 + 129
60 u = 2820

1 u = 2820 ÷ 60 = 47

Number of blue stickers
= 7 u - 299
= 7 x 47 - 299
= 329 - 299
= 30

(b)
Number of green stickers
= 3 u
= 3 x 47
= 141

Answer(s): (a) 30; (b) 141