The ratio of silver to red stamps that Shannon had was 4 : 3. The cost of each of the silver stamps was $4 and the cost of each of the red stamps was $7. Shannon sold 50% of the silver stamps and the total cost of the unsold stamps was $290. How many red stamps did she have left?
| |
Silver stamps |
Red stamps |
| Before |
4 u |
3 u |
| Change |
- 2 u |
|
| After |
2 u |
3 u |
Number of silver stamps sold
= 50% x 4 u
=
50100 x 4 u
= 2 u
| |
Silver stamps |
Red stamps |
Total |
| Number |
2 u |
3 u |
|
| Value |
$4 |
$7 |
|
| Total value |
8 u |
21 u |
$290 |
Total cost of unsold stamps
= 8 u + 21 u
= 29 u
29 u = 290
1 u = 290 ÷ 29 = 10
Number of red stamps that Shannon had left
= 21 u
= 21 x 10
= 210
Answer(s): 210
