The ratio of gold to purple stamps that Hilda had was 5 : 2. The cost of each of the gold stamps was $5 and the cost of each of the purple stamps was $10. Hilda sold 60% of the gold stamps and the total cost of the unsold stamps was $360. How many purple stamps did she have left?
| |
Gold stamps |
Purple stamps |
| Before |
5 u |
2 u |
| Change |
- 3 u |
|
| After |
2 u |
2 u |
Number of gold stamps sold
= 60% x 5 u
=
60100 x 5 u
= 3 u
| |
Gold stamps |
Purple stamps |
Total |
| Number |
2 u |
2 u |
|
| Value |
$5 |
$10 |
|
| Total value |
10 u |
20 u |
$360 |
Total cost of unsold stamps
= 10 u + 20 u
= 30 u
30 u = 360
1 u = 360 ÷ 30 = 12
Number of purple stamps that Hilda had left
= 20 u
= 20 x 12
= 240
Answer(s): 240
