The ratio of red to blue stamps that Cindy had was 4 : 3. The cost of each of the red stamps was $3 and the cost of each of the blue stamps was $8. Cindy sold 25% of the red stamps and the total cost of the unsold stamps was $396. How many blue stamps did she have left?
| |
Red stamps |
Blue stamps |
| Before |
4 u |
3 u |
| Change |
- 1 u |
|
| After |
3 u |
3 u |
Number of red stamps sold
= 25% x 4 u
=
25100 x 4 u
= 1 u
| |
Red stamps |
Blue stamps |
Total |
| Number |
3 u |
3 u |
|
| Value |
$3 |
$8 |
|
| Total value |
9 u |
24 u |
$396 |
Total cost of unsold stamps
= 9 u + 24 u
= 33 u
33 u = 396
1 u = 396 ÷ 33 = 12
Number of blue stamps that Cindy had left
= 24 u
= 24 x 12
= 288
Answer(s): 288
