Adam has 600 red and blue stickers.
He sells 20 red stickers and the number of blue stickers becomes 3 times as many as red stickers.
- How many more blue stickers than red stickers does Adam have at first?
- How many less red stickers than blue stickers does Adam have in the end?
|
Red |
Blue |
Before |
1 u + 20 |
3 u |
Change |
- 20 |
No Change |
After |
1 u |
3 u |
(a)
The number of blue stickers remains unchanged.
Total number of stickers at first
= 1 u + 20 + 3 u
= 4 u + 20
4 u + 20 = 600
4 u = 600 - 20
4 u = 580
1 u = 580 ÷ 4 = 145
Number of more blue stickers than red stickers at first
= 3 u - (1 u + 20)
= 3 u - 1 u - 20
= 2 u - 20
= 2 x 145 - 20
= 290 - 20
= 270
(b)
Number of less red stickers than blue stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 145
= 290
Answer(s): (a) 270; (b) 290