The ratio of blue to yellow stamps that Xuan had was 5 : 3. The cost of each of the blue stamps was $1 and the cost of each of the yellow stamps was $2. Xuan sold 60% of the blue stamps and the total cost of the unsold stamps was $16. How many blue stamps did she have left?
| |
Blue stamps |
Yellow stamps |
| Before |
5 u |
3 u |
| Change |
- 3 u |
|
| After |
2 u |
3 u |
Number of blue stamps sold
= 60% x 5 u
=
60100 x 5 u
= 3 u
| |
Blue stamps |
Yellow stamps |
Total |
| Number |
2 u |
3 u |
|
| Value |
$1 |
$2 |
|
| Total value |
2 u |
6 u |
$16 |
Total cost of unsold stamps
= 2 u + 6 u
= 8 u
8 u = 16
1 u = 16 ÷ 8 = 2
Number of blue stamps that Xuan had left
= 2 u
= 2 x 2
= 4
Answer(s): 4
