The ratio of brown to pink stamps that Usha had was 4 : 3. The cost of each of the brown stamps was $5 and the cost of each of the pink stamps was $7. Usha sold 50% of the brown stamps and the total cost of the unsold stamps was $310. How many pink stamps did she have left?
|
Brown stamps |
Pink 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 |
Pink stamps |
Total |
Number |
2 u |
3 u |
|
Value |
$5 |
$7 |
|
Total value |
10 u |
21 u |
$310 |
Total cost of unsold stamps
= 10 u + 21 u
= 31 u
31 u = 310
1 u = 310 ÷ 31 = 10
Number of pink stamps that Usha had left
= 21 u
= 21 x 10
= 210
Answer(s): 210