Adam has 800 blue and red stickers.
He buys 40 blue stickers and the number of blue stickers becomes 3 times as many as red stickers.
- How many more blue stickers than red stickers does Adam have at first?
- How many less red stickers than blue stickers does Adam have in the end?
|
Blue |
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 = 800
4 u = 800 + 40
4 u = 840
1 u = 840 ÷ 4 = 210
Number of more blue stickers than red stickers at first
= (3 u - 40) - 1 u
= 3 u - 1 u - 40
= 2 u - 40
= 2 x 210 - 40
= 420 - 40
= 380
(b)
Number of less red stickers than blue stickers in the end
= 3 u - 1 u
= 2 u
= 2 x 210
= 420
Answer(s): (a) 380; (b) 420