The ratio of brown to yellow stamps that Diana had was 5 : 2. The cost of each of the brown stamps was $2 and the cost of each of the yellow stamps was $5. Diana sold 60% of the brown stamps and the total cost of the unsold stamps was $168. How many yellow stamps did she have left?
| |
Brown stamps |
Yellow stamps |
| Before |
5 u |
2 u |
| Change |
- 3 u |
|
| After |
2 u |
2 u |
Number of brown stamps sold
= 60% x 5 u
=
60100 x 5 u
= 3 u
| |
Brown stamps |
Yellow stamps |
Total |
| Number |
2 u |
2 u |
|
| Value |
$2 |
$5 |
|
| Total value |
4 u |
10 u |
$168 |
Total cost of unsold stamps
= 4 u + 10 u
= 14 u
14 u = 168
1 u = 168 ÷ 14 = 12
Number of yellow stamps that Diana had left
= 10 u
= 10 x 12
= 120
Answer(s): 120
