The ratio of blue to red stamps that Rachel had was 4 : 3. The cost of each of the blue stamps was $5 and the cost of each of the red stamps was $9. Rachel sold 50% of the blue stamps and the total cost of the unsold stamps was $407. How many red stamps did she have left?
| |
Blue stamps |
Red stamps |
| Before |
4 u |
3 u |
| Change |
- 2 u |
|
| After |
2 u |
3 u |
Number of blue stamps sold
= 50% x 4 u
=
50100 x 4 u
= 2 u
| |
Blue stamps |
Red stamps |
Total |
| Number |
2 u |
3 u |
|
| Value |
$5 |
$9 |
|
| Total value |
10 u |
27 u |
$407 |
Total cost of unsold stamps
= 10 u + 27 u
= 37 u
37 u = 407
1 u = 407 ÷ 37 = 11
Number of red stamps that Rachel had left
= 27 u
= 27 x 11
= 297
Answer(s): 297
