The ratio of grey to purple stamps that Wendy had was 5 : 3. The cost of each of the grey stamps was $2 and the cost of each of the purple stamps was $4. Wendy sold 20% of the grey stamps and the total cost of the unsold stamps was $200. How many grey stamps did she have left?
| |
Grey stamps |
Purple stamps |
| Before |
5 u |
3 u |
| Change |
- 1 u |
|
| After |
4 u |
3 u |
Number of grey stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Grey stamps |
Purple stamps |
Total |
| Number |
4 u |
3 u |
|
| Value |
$2 |
$4 |
|
| Total value |
8 u |
12 u |
$200 |
Total cost of unsold stamps
= 8 u + 12 u
= 20 u
20 u = 200
1 u = 200 ÷ 20 = 10
Number of grey stamps that Wendy had left
= 8 u
= 8 x 10
= 80
Answer(s): 80
