The ratio of brown to gold stamps that Dana had was 5 : 4. The cost of each of the brown stamps was $1 and the cost of each of the gold stamps was $4. Dana sold 20% of the brown stamps and the total cost of the unsold stamps was $160. How many gold stamps did she have left?
| |
Brown stamps |
Gold stamps |
| Before |
5 u |
4 u |
| Change |
- 1 u |
|
| After |
4 u |
4 u |
Number of brown stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Brown stamps |
Gold stamps |
Total |
| Number |
4 u |
4 u |
|
| Value |
$1 |
$4 |
|
| Total value |
4 u |
16 u |
$160 |
Total cost of unsold stamps
= 4 u + 16 u
= 20 u
20 u = 160
1 u = 160 ÷ 20 = 8
Number of gold stamps that Dana had left
= 16 u
= 16 x 8
= 128
Answer(s): 128
