Adam has 400 green and red stickers.
He buys 80 green stickers and the number of green stickers becomes 3 times as many as red stickers.
- How many more green stickers than red stickers does Adam have at first?
- How many less red stickers than green stickers does Adam have in the end?
|
Green |
Red |
Before |
3 u - 80 |
1 u |
Change |
+ 80 |
No change |
After |
3 u |
1 u |
(a)
The number of red stickers remain unchanged.
Total number of stickers at first
= 1 u + 3 u - 80
= 4 u - 80
4 u - 80 = 400
4 u = 400 + 80
4 u = 480
1 u = 480 ÷ 4 = 120
Number of more green stickers than red stickers at first
= (3 u - 80) - 1 u
= 3 u - 1 u - 80
= 2 u - 80
= 2 x 120 - 80
= 240 - 80
= 160
(b)
Number of less red stickers than green stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 120
= 240
Answer(s): (a) 160; (b) 240