Adam has 70 more stickers than Charlie.
After Charlie gives away 20 stickers,
Adam has 4 times as many stickers as Charlie.
- How many stickers does Charlie have at first?
- How many stickers does Adam have?
- How many stickers do they have altogether at first?
- How many stickers do they have altogether in the end?
|
Adam |
Charlie |
Before |
1 u + 20 + 70 |
1 u + 20 |
Change |
No change |
- 20 |
After |
4 u |
1 u |
(a)
The number of stickers that Adam has at first and in the end remains unchanged.
Number of stickers that Adam has at first = Number of stickers that Adam has in the end
1 u + 20 + 70 = 4 u
1 u + 90 = 4 u
4 u - 1 u = 90
3 u = 90
1 u = 90 ÷ 3 = 30
Number of stickers that Charlie has
= 1 u + 20
= 30 + 20
= 50
(b)
Number of stickers that Adam has
= 4 u
= 4 x 30
= 120
(c)
Number of stickers that they have altogether at first
= 1 u + 20 + 70 + 1 u + 20
= 1 u + 1 u + 20 + 70 + 20
= 2 u + 110
= 2 x 30 + 110
= 60 + 110
= 170
(d)
Number of stickers that they have altogether in the end
= 4 u + 1 u
= 5 u
= 5 x 30
= 150
Answer(s): (a) 50; (b) 120; (c) 170; (d) 150