If 312 red stickers are added, 40% of the stickers will be green stickers.
If 212 green stickers are added, 25% of the stickers will be red stickers.

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

	Scenario 1		Scenario 2
	Red	Green	Red	Green
Before	3 u - 312	2 u	1 p	3 p - 212
Change	+ 312	No change	No change	+ 212
After	3 u	2 u	1 p	3 p

(a)
40% = ⁴⁰₁₀₀ = ²₅
25% = ²⁵₁₀₀ = ¹₄

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

Number of red stickers at first = 3 u - 312
Number of green stickers at first = 2 u

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

Number of red stickers at first = 1 p
Number of green stickers at first = 3 p - 212

3 u - 312 = 1 p --- (1)

2 u = 3 p - 212
2 u + 212 = 3 p --- (2)

(1) _{x 3}
9 u - 936 = 3 p --- (3)

(3) = (2)
9 u - 936 = 2 u + 212
9 u - 2 u = 936 + 212
7 u = 1148

1 u = 1148 ÷ 7 = 164

Number of red stickers
= 3 u - 312
= 3 x 164 - 312
= 492 - 312
= 180

(b)
Number of green stickers
= 2 u
= 2 x 164
= 328

Answer(s): (a) 180; (b) 328