Bryan has 20 more stickers than Adam.
After Adam gives away 20 stickers,
Bryan has 3 times as many stickers as Adam.
- How many stickers does Adam have at first?
- How many stickers does Bryan have?
- How many stickers do they have altogether at first?
- How many stickers do they have altogether in the end?
|
Bryan |
Adam |
Before |
1 u + 20 + 20 |
1 u + 20 |
Change |
No change |
- 20 |
After |
3 u |
1 u |
(a)
The number of stickers that Bryan has at first and in the end remains unchanged.
Number of stickers that Bryan has at first = Number of stickers that Bryan has in the end
1 u + 20 + 20 = 3 u
1 u + 40 = 3 u
3 u - 1 u = 40
2 u = 40
1 u = 40 ÷ 2 = 20
Number of stickers that Adam has
= 1 u + 20
= 20 + 20
= 40
(b)
Number of stickers that Bryan has
= 3 u
= 3 x 20
= 60
(c)
Number of stickers that they have altogether at first
= 1 u + 20 + 20 + 1 u + 20
= 1 u + 1 u + 20 + 20 + 20
= 2 u + 60
= 2 x 20 + 60
= 40 + 60
= 100
(d)
Number of stickers that they have altogether in the end
= 3 u + 1 u
= 4 u
= 4 x 20
= 80
Answer(s): (a) 40; (b) 60; (c) 100; (d) 80