The ratio of blue to pink stamps that Nora had was 5 : 3. The cost of each of the blue stamps was $4 and the cost of each of the pink stamps was $7. Nora sold 20% of the blue stamps and the total cost of the unsold stamps was $407. How many pink stamps did she have left?
| |
Blue stamps |
Pink stamps |
| Before |
5 u |
3 u |
| Change |
- 1 u |
|
| After |
4 u |
3 u |
Number of blue stamps sold
= 20% x 5 u
=
20100 x 5 u
= 1 u
| |
Blue stamps |
Pink stamps |
Total |
| Number |
4 u |
3 u |
|
| Value |
$4 |
$7 |
|
| Total value |
16 u |
21 u |
$407 |
Total cost of unsold stamps
= 16 u + 21 u
= 37 u
37 u = 407
1 u = 407 ÷ 37 = 11
Number of pink stamps that Nora had left
= 21 u
= 21 x 11
= 231
Answer(s): 231
