Adam has 800 red and green stickers.
He buys 70 red stickers and the number of red stickers becomes 2 times as many as green stickers.
- How many more red stickers than green stickers does Adam have at first?
- How many less green stickers than red stickers does Adam have in the end?
|
Red |
Green |
Before |
2 u - 70 |
1 u |
Change |
+ 70 |
No change |
After |
2 u |
1 u |
(a)
The number of green stickers remain unchanged.
Total number of stickers at first
= 1 u + 2 u - 70
= 3 u - 70
3 u - 70 = 800
3 u = 800 + 70
3 u = 870
1 u = 870 ÷ 3 = 290
Number of more red stickers than green stickers at first
= (2 u - 70) - 1 u
= 2 u - 1 u - 70
= 1 u - 70
= 1 x 290 - 70
= 290 - 70
= 220
(b)
Number of less green stickers than red stickers in the end
= 2 u - 1 u
= 1 u
= 1 x 290
= 290
Answer(s): (a) 220; (b) 290