Adam has 400 green and red stickers.
He buys 40 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 - 40 |
1 u |
Change |
+ 40 |
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 - 40
= 4 u - 40
4 u - 40 = 400
4 u = 400 + 40
4 u = 440
1 u = 440 ÷ 4 = 110
Number of more green stickers than red stickers at first
= (3 u - 40) - 1 u
= 3 u - 1 u - 40
= 2 u - 40
= 2 x 110 - 40
= 220 - 40
= 180
(b)
Number of less red stickers than green stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 110
= 220
Answer(s): (a) 180; (b) 220