Adam has 200 blue and green stickers.
He buys 20 blue stickers and the number of blue stickers becomes 3 times as many as green stickers.
- How many more blue stickers than green stickers does Adam have at first?
- How many less green stickers than blue stickers does Adam have in the end?
|
Blue |
Green |
Before |
3 u - 20 |
1 u |
Change |
+ 20 |
No change |
After |
3 u |
1 u |
(a)
The number of green stickers remain unchanged.
Total number of stickers at first
= 1 u + 3 u - 20
= 4 u - 20
4 u - 20 = 200
4 u = 200 + 20
4 u = 220
1 u = 220 ÷ 4 = 55
Number of more blue stickers than green stickers at first
= (3 u - 20) - 1 u
= 3 u - 1 u - 20
= 2 u - 20
= 2 x 55 - 20
= 110 - 20
= 90
(b)
Number of less green stickers than blue stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 55
= 110
Answer(s): (a) 90; (b) 110