In a box of notes, the number of $10, $20 and $50 are in ratio of 7 : 5 : 2.
37 of the $10-notes and 15 $20-notes are taken out. The remaining notes are worth $2580. Find the difference between the value of $50-notes and $10-notes in the end.
| |
$10 |
$20 |
$50 |
| Before |
7 u |
5 u |
2 u |
| Change |
- 3 u |
- 15 |
|
| After |
4 u |
5 u - 15 |
2 u |
| |
$10 |
$20 |
$50 |
Total |
| Number |
4 u |
5 u - 15 |
2 u |
|
| Value |
10 |
20 |
50 |
|
| Total value |
40 u |
100 u - 300 |
100 u |
2580 |
Total value of the notes
= 40 u + 100 u - 300 + 100 u
= 240 u - 300
240 u - 300 = 2580
240 u = 2580 + 300
240 u = 2880
1 u = 2880 ÷ 240 = 12
Difference between the value of $50-notes and $10-notes in the end
= 100 u - 40 u
= 60 u
= 60 x 12
= $720
Answer(s): $720
