The ratio of gold to purple stamps that Hazel had was 5 : 4. The cost of each of the gold stamps was $4 and the cost of each of the purple stamps was $9. Hazel sold 40% of the gold stamps and the total cost of the unsold stamps was $144. How many purple stamps did she have left?
| |
Gold stamps |
Purple stamps |
| Before |
5 u |
4 u |
| Change |
- 2 u |
|
| After |
3 u |
4 u |
Number of gold stamps sold
= 40% x 5 u
=
40100 x 5 u
= 2 u
| |
Gold stamps |
Purple stamps |
Total |
| Number |
3 u |
4 u |
|
| Value |
$4 |
$9 |
|
| Total value |
12 u |
36 u |
$144 |
Total cost of unsold stamps
= 12 u + 36 u
= 48 u
48 u = 144
1 u = 144 ÷ 48 = 3
Number of purple stamps that Hazel had left
= 36 u
= 36 x 3
= 108
Answer(s): 108
