Adam has 100 blue and red stickers.
He sells 20 blue stickers and the number of red stickers becomes 3 times as many as blue stickers.
- How many more red stickers than blue stickers does Adam have at first?
- How many less blue stickers than red stickers does Adam have in the end?
|
Blue |
Red |
Before |
1 u + 20 |
3 u |
Change |
- 20 |
No Change |
After |
1 u |
3 u |
(a)
The number of red stickers remains unchanged.
Total number of stickers at first
= 1 u + 20 + 3 u
= 4 u + 20
4 u + 20 = 100
4 u = 100 - 20
4 u = 80
1 u = 80 ÷ 4 = 20
Number of more red stickers than blue stickers at first
= 3 u - (1 u + 20)
= 3 u - 1 u - 20
= 2 u - 20
= 2 x 20 - 20
= 40 - 20
= 20
(b)
Number of less blue stickers than red stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 20
= 40
Answer(s): (a) 20; (b) 40