The ratio of white to pink stamps that Sabrina had was 5 : 4. The cost of each of the white stamps was $3 and the cost of each of the pink stamps was $6. Sabrina sold 20% of the white stamps and the total cost of the unsold stamps was $108. How many pink stamps did she have left?
| |
White stamps |
Pink stamps |
| Before |
5 u |
4 u |
| Change |
- 1 u |
|
| After |
4 u |
4 u |
Number of white stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
White stamps |
Pink stamps |
Total |
| Number |
4 u |
4 u |
|
| Value |
$3 |
$6 |
|
| Total value |
12 u |
24 u |
$108 |
Total cost of unsold stamps
= 12 u + 24 u
= 36 u
36 u = 108
1 u = 108 ÷ 36 = 3
Number of pink stamps that Sabrina had left
= 24 u
= 24 x 3
= 72
Answer(s): 72
