The ratio of yellow to gold stamps that Barbara had was 5 : 3. The cost of each of the yellow stamps was $4 and the cost of each of the gold stamps was $5. Barbara sold 40% of the yellow stamps and the total cost of the unsold stamps was $54. How many gold stamps did she have left?
| |
Yellow stamps |
Gold stamps |
| Before |
5 u |
3 u |
| Change |
- 2 u |
|
| After |
3 u |
3 u |
Number of yellow stamps sold
= 40% x 5 u
=
40100 x 5 u
= 2 u
| |
Yellow stamps |
Gold stamps |
Total |
| Number |
3 u |
3 u |
|
| Value |
$4 |
$5 |
|
| Total value |
12 u |
15 u |
$54 |
Total cost of unsold stamps
= 12 u + 15 u
= 27 u
27 u = 54
1 u = 54 ÷ 27 = 2
Number of gold stamps that Barbara had left
= 15 u
= 15 x 2
= 30
Answer(s): 30
