Mark, Paul and Zane had some stamps in the ratio of 2 : 3 : 5. Zane gave 40% of his stamps to Mark and Paul. As a result, Mark had the same number of stamps as Paul and Zane had 20 fewer stamps than Mark.
- What was the percentage increase in Mark's stamps after receiving from Zane?
- How many stamps did Paul have at first?
| Mark |
Paul |
Zane |
Total |
| 2 u |
3 u |
5 u |
10 u |
| + 2 u |
- 2 u |
|
| 3.5 u |
3.5 u |
3 u |
10 u |
(a)
Number of stamps that Zane gave away
= 40% x 5
=
40100 x 5
= 2 u
Number of stamps that Mark and Paul each had in the end
= (10 u - 3 u) ÷ 2
= 7 u ÷ 2
= 3.5 u
Increase in the number of stamps that Mark had
= 3.5 u - 2 u
= 1.5 u
Percentage increase in Mark's stamps after receiving from Zane
=
1.52 x 100%
= 75%
(b)
3.5 u = 3 u + 20
3.5 u - 3 u = 20
0.5 u = 20
1 u = 20 ÷ 0.5 = 40
Number of stamps that Paul had at first
= 3 u
= 3 x 40
= 120
Answer(s): (a) 75%; (b) 120
