The ratio of green to black stamps that Fiona had was 4 : 3. The cost of each of the green stamps was $3 and the cost of each of the black stamps was $6. Fiona sold 25% of the green stamps and the total cost of the unsold stamps was $297. How many green stamps did she have left?
| |
Green stamps |
Black stamps |
| Before |
4 u |
3 u |
| Change |
- 1 u |
|
| After |
3 u |
3 u |
Number of green stamps sold
= 25% x 4 u
=
25100 x 4 u
= 1 u
| |
Green stamps |
Black stamps |
Total |
| Number |
3 u |
3 u |
|
| Value |
$3 |
$6 |
|
| Total value |
9 u |
18 u |
$297 |
Total cost of unsold stamps
= 9 u + 18 u
= 27 u
27 u = 297
1 u = 297 ÷ 27 = 11
Number of green stamps that Fiona had left
= 9 u
= 9 x 11
= 99
Answer(s): 99
