The ratio of brown to gold stamps that Gem had was 5 : 3. The cost of each of the brown stamps was $4 and the cost of each of the gold stamps was $7. Gem sold 20% of the brown stamps and the total cost of the unsold stamps was $333. How many gold stamps did she have left?
| |
Brown stamps |
Gold stamps |
| Before |
5 u |
3 u |
| Change |
- 1 u |
|
| After |
4 u |
3 u |
Number of brown stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Brown stamps |
Gold stamps |
Total |
| Number |
4 u |
3 u |
|
| Value |
$4 |
$7 |
|
| Total value |
16 u |
21 u |
$333 |
Total cost of unsold stamps
= 16 u + 21 u
= 37 u
37 u = 333
1 u = 333 ÷ 37 = 9
Number of gold stamps that Gem had left
= 21 u
= 21 x 9
= 189
Answer(s): 189
