The ratio of grey to blue stamps that Emily had was 5 : 4. The cost of each of the grey stamps was $2 and the cost of each of the blue stamps was $6. Emily sold 60% of the grey stamps and the total cost of the unsold stamps was $196. How many blue stamps did she have left?
| |
Grey stamps |
Blue stamps |
| Before |
5 u |
4 u |
| Change |
- 3 u |
|
| After |
2 u |
4 u |
Number of grey stamps sold
= 60% x 5 u
=
60100 x 5 u
= 3 u
| |
Grey stamps |
Blue stamps |
Total |
| Number |
2 u |
4 u |
|
| Value |
$2 |
$6 |
|
| Total value |
4 u |
24 u |
$196 |
Total cost of unsold stamps
= 4 u + 24 u
= 28 u
28 u = 196
1 u = 196 ÷ 28 = 7
Number of blue stamps that Emily had left
= 24 u
= 24 x 7
= 168
Answer(s): 168
