Adam has 100 red and blue stickers.
He buys 20 red stickers and the number of red stickers becomes 4 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?
|
Red |
Blue |
Before |
4 u - 20 |
1 u |
Change |
+ 20 |
No change |
After |
4 u |
1 u |
(a)
The number of blue stickers remain unchanged.
Total number of stickers at first
= 1 u + 4 u - 20
= 5 u - 20
5 u - 20 = 100
5 u = 100 + 20
5 u = 120
1 u = 120 ÷ 5 = 24
Number of more red stickers than blue stickers at first
= (4 u - 20) - 1 u
= 4 u - 1 u - 20
= 3 u - 20
= 3 x 24 - 20
= 72 - 20
= 52
(b)
Number of less blue stickers than red stickers in the end
= 4 u - 1 u
= 3 u
= 3 x 24
= 72
Answer(s): (a) 52; (b) 72