If 170 green stickers are added, 40% of the stickers will be red stickers.
If 155 red stickers are added, 25% of the stickers will be green stickers.

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

	Scenario 1		Scenario 2
	Green	Red	Green	Red
Before	3 u - 170	2 u	1 p	3 p - 155
Change	+ 170	No change	No change	+ 155
After	3 u	2 u	1 p	3 p

(a)
40% = ⁴⁰₁₀₀ = ²₅
25% = ²⁵₁₀₀ = ¹₄

Scenario 1
Fraction of the stickers that are green
= 1 - ²₅
= ³₅

Number of green stickers at first = 3 u - 170
Number of red stickers at first = 2 u

Scenario 2
Fraction of the stickers that are red
= 1 - ¹₄
= ³₄

Number of green stickers at first = 1 p
Number of red stickers at first = 3 p - 155

3 u - 170 = 1 p --- (1)

2 u = 3 p - 155
2 u + 155 = 3 p --- (2)

(1) _{x 3}
9 u - 510 = 3 p --- (3)

(3) = (2)
9 u - 510 = 2 u + 155
9 u - 2 u = 510 + 155
7 u = 665

1 u = 665 ÷ 7 = 95

Number of green stickers
= 3 u - 170
= 3 x 95 - 170
= 285 - 170
= 115

(b)
Number of red stickers
= 2 u
= 2 x 95
= 190

Answer(s): (a) 115; (b) 190