Adam has some red stickers and blue stickers.
If Adam receives another 1020 blue stickers,
the red stickers will be 20% as many as the blue stickers.
If Adam receives another 21 red stickers,
the red stickers will be 80% as many as the blue stickers.

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

	Scenario 1		Scenario 2
	Red	Blue	Red	Blue
Before	1 u	5 u - 1020	4 p - 21	5 p
Change	No change	+ 1020	+ 21	No change
After	1 u	5 u	4 p	5 p

(a)
20% = ²⁰₁₀₀ = ¹₅
80% = ⁸⁰₁₀₀ = ⁴₅

Scenario 1
Number of red stickers at first = 1 u
Number of blue stickers at first = 5 u - 1020

Scenario 2
Number of red stickers at first = 4 p - 21
Number of blue stickers at first = 5 p

1 u = 4 p - 21 --- (1)
5 u - 1020 = 5 p --- (2)

(2) _{÷ 5}
1 u - 204 = 1 p
1 u = 1 p + 204 --- (3)

(1) = (3)
4 p - 21 = 1 p + 204
4 p - 1 p = 21 + 204
3 p = 225

1 p = 225 ÷ 3 = 75

Number of red stickers
= 4 p - 21
= 4 x 75 - 21
= 300 - 21
= 279

(b)
Number of blue stickers
= 5 p
= 5 x 75
= 375

Answer(s): (a) 279; (b) 375