The ratio of pink to grey stamps that Victoria had was 4 : 3. The cost of each of the pink stamps was $4 and the cost of each of the grey stamps was $6. Victoria sold 25% of the pink stamps and the total cost of the unsold stamps was $120. How many grey stamps did she have left?
| |
Pink stamps |
Grey stamps |
| Before |
4 u |
3 u |
| Change |
- 1 u |
|
| After |
3 u |
3 u |
Number of pink stamps sold
= 25% x 4 u
=
25100 x 4 u
= 1 u
| |
Pink stamps |
Grey stamps |
Total |
| Number |
3 u |
3 u |
|
| Value |
$4 |
$6 |
|
| Total value |
12 u |
18 u |
$120 |
Total cost of unsold stamps
= 12 u + 18 u
= 30 u
30 u = 120
1 u = 120 ÷ 30 = 4
Number of grey stamps that Victoria had left
= 18 u
= 18 x 4
= 72
Answer(s): 72
