Adam has 700 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 = 700
4 u = 700 + 80
4 u = 780
1 u = 780 ÷ 4 = 195
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 195 - 80
= 390 - 80
= 310
(b)
Number of less blue stickers than red stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 195
= 390
Answer(s): (a) 310; (b) 390