Adam has 50 more stickers than Charlie.
After Charlie gives away 20 stickers,
Adam has 3 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 + 50 |
1 u + 20 |
Change |
No change |
- 20 |
After |
3 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 + 50 = 3 u
1 u + 70 = 3 u
3 u - 1 u = 70
2 u = 70
1 u = 70 ÷ 2 = 35
Number of stickers that Charlie has
= 1 u + 20
= 35 + 20
= 55
(b)
Number of stickers that Adam has
= 3 u
= 3 x 35
= 105
(c)
Number of stickers that they have altogether at first
= 1 u + 20 + 50 + 1 u + 20
= 1 u + 1 u + 20 + 50 + 20
= 2 u + 90
= 2 x 35 + 90
= 70 + 90
= 160
(d)
Number of stickers that they have altogether in the end
= 3 u + 1 u
= 4 u
= 4 x 35
= 140
Answer(s): (a) 55; (b) 105; (c) 160; (d) 140