The ratio of blue to silver stamps that Elyse had was 5 : 2. The cost of each of the blue stamps was $2 and the cost of each of the silver stamps was $6. Elyse sold 20% of the blue stamps and the total cost of the unsold stamps was $60. How many silver stamps did she have left?
| |
Blue stamps |
Silver stamps |
| Before |
5 u |
2 u |
| Change |
- 1 u |
|
| After |
4 u |
2 u |
Number of blue stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Blue stamps |
Silver stamps |
Total |
| Number |
4 u |
2 u |
|
| Value |
$2 |
$6 |
|
| Total value |
8 u |
12 u |
$60 |
Total cost of unsold stamps
= 8 u + 12 u
= 20 u
20 u = 60
1 u = 60 ÷ 20 = 3
Number of silver stamps that Elyse had left
= 12 u
= 12 x 3
= 36
Answer(s): 36
