Adam has 900 red and blue stickers.
He buys 80 red 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?
|
Red |
Blue |
Before |
3 u - 80 |
1 u |
Change |
+ 80 |
No change |
After |
3 u |
1 u |
(a)
The number of blue stickers remain unchanged.
Total number of stickers at first
= 1 u + 3 u - 80
= 4 u - 80
4 u - 80 = 900
4 u = 900 + 80
4 u = 980
1 u = 980 ÷ 4 = 245
Number of more red stickers than blue stickers at first
= (3 u - 80) - 1 u
= 3 u - 1 u - 80
= 2 u - 80
= 2 x 245 - 80
= 490 - 80
= 410
(b)
Number of less blue stickers than red stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 245
= 490
Answer(s): (a) 410; (b) 490