The ratio of blue to brown stamps that Emily had was 5 : 2. The cost of each of the blue stamps was $3 and the cost of each of the brown stamps was $4. Emily sold 40% of the blue stamps and the total cost of the unsold stamps was $102. How many brown stamps did she have left?
| |
Blue stamps |
Brown stamps |
| Before |
5 u |
2 u |
| Change |
- 2 u |
|
| After |
3 u |
2 u |
Number of blue stamps sold
= 40% x 5 u
=
40100 x 5 u
= 2 u
| |
Blue stamps |
Brown stamps |
Total |
| Number |
3 u |
2 u |
|
| Value |
$3 |
$4 |
|
| Total value |
9 u |
8 u |
$102 |
Total cost of unsold stamps
= 9 u + 8 u
= 17 u
17 u = 102
1 u = 102 ÷ 17 = 6
Number of brown stamps that Emily had left
= 8 u
= 8 x 6
= 48
Answer(s): 48
