The ratio of green to grey stamps that Risa had was 4 : 3. The cost of each of the green stamps was $3 and the cost of each of the grey stamps was $6. Risa sold 50% of the green stamps and the total cost of the unsold stamps was $48. How many green stamps did she have left?
| |
Green stamps |
Grey stamps |
| Before |
4 u |
3 u |
| Change |
- 2 u |
|
| After |
2 u |
3 u |
Number of green stamps sold
= 50% x 4 u
=
50100 x 4 u
= 2 u
| |
Green stamps |
Grey stamps |
Total |
| Number |
2 u |
3 u |
|
| Value |
$3 |
$6 |
|
| Total value |
6 u |
18 u |
$48 |
Total cost of unsold stamps
= 6 u + 18 u
= 24 u
24 u = 48
1 u = 48 ÷ 24 = 2
Number of green stamps that Risa had left
= 6 u
= 6 x 2
= 12
Answer(s): 12
