The ratio of green to red stamps that Hilda had was 5 : 3. The cost of each of the green stamps was $4 and the cost of each of the red stamps was $8. Hilda sold 40% of the green stamps and the total cost of the unsold stamps was $108. How many red stamps did she have left?
| |
Green stamps |
Red stamps |
| Before |
5 u |
3 u |
| Change |
- 2 u |
|
| After |
3 u |
3 u |
Number of green stamps sold
= 40% x 5 u
=
40100 x 5 u
= 2 u
| |
Green stamps |
Red stamps |
Total |
| Number |
3 u |
3 u |
|
| Value |
$4 |
$8 |
|
| Total value |
12 u |
24 u |
$108 |
Total cost of unsold stamps
= 12 u + 24 u
= 36 u
36 u = 108
1 u = 108 ÷ 36 = 3
Number of red stamps that Hilda had left
= 24 u
= 24 x 3
= 72
Answer(s): 72
