The ratio of white to purple stamps that Emily had was 5 : 2. The cost of each of the white stamps was $5 and the cost of each of the purple stamps was $6. Emily sold 40% of the white stamps and the total cost of the unsold stamps was $135. How many white stamps did she have left?
| |
White stamps |
Purple stamps |
| Before |
5 u |
2 u |
| Change |
- 2 u |
|
| After |
3 u |
2 u |
Number of white stamps sold
= 40% x 5 u
=
40100 x 5 u
= 2 u
| |
White stamps |
Purple stamps |
Total |
| Number |
3 u |
2 u |
|
| Value |
$5 |
$6 |
|
| Total value |
15 u |
12 u |
$135 |
Total cost of unsold stamps
= 15 u + 12 u
= 27 u
27 u = 135
1 u = 135 ÷ 27 = 5
Number of white stamps that Emily had left
= 15 u
= 15 x 5
= 75
Answer(s): 75
