The ratio of brown to grey stamps that Tiffany had was 4 : 3. The cost of each of the brown stamps was $4 and the cost of each of the grey stamps was $6. Tiffany sold 50% of the brown stamps and the total cost of the unsold stamps was $156. How many grey stamps did she have left?
| |
Brown stamps |
Grey stamps |
| Before |
4 u |
3 u |
| Change |
- 2 u |
|
| After |
2 u |
3 u |
Number of brown stamps sold
= 50% x 4 u
=
50100 x 4 u
= 2 u
| |
Brown stamps |
Grey stamps |
Total |
| Number |
2 u |
3 u |
|
| Value |
$4 |
$6 |
|
| Total value |
8 u |
18 u |
$156 |
Total cost of unsold stamps
= 8 u + 18 u
= 26 u
26 u = 156
1 u = 156 ÷ 26 = 6
Number of grey stamps that Tiffany had left
= 18 u
= 18 x 6
= 108
Answer(s): 108
