The ratio of white to purple stamps that Sabrina had was 5 : 2. The cost of each of the white stamps was $4 and the cost of each of the purple stamps was $5. Sabrina sold 40% of the white stamps and the total cost of the unsold stamps was $132. 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 |
$4 |
$5 |
|
| Total value |
12 u |
10 u |
$132 |
Total cost of unsold stamps
= 12 u + 10 u
= 22 u
22 u = 132
1 u = 132 ÷ 22 = 6
Number of white stamps that Sabrina had left
= 12 u
= 12 x 6
= 72
Answer(s): 72
