In a box of notes, the number of $10, $20 and $100 are in ratio of 6 : 3 : 4.
16 of the $10-notes and 7 $20-notes are taken out. The remaining notes are worth $2920. Find the difference between the value of $100-notes and $10-notes in the end.
| |
$10 |
$20 |
$100 |
| Before |
6 u |
3 u |
4 u |
| Change |
- 1 u |
- 7 |
|
| After |
5 u |
3 u - 7 |
4 u |
| |
$10 |
$20 |
$100 |
Total |
| Number |
5 u |
3 u - 7 |
4 u |
|
| Value |
10 |
20 |
100 |
|
| Total value |
50 u |
60 u - 140 |
400 u |
2920 |
Total value of the notes
= 50 u + 60 u - 140 + 400 u
= 510 u - 140
510 u - 140 = 2920
510 u = 2920 + 140
510 u = 3060
1 u = 3060 ÷ 510 = 6
Difference between the value of $100-notes and $10-notes in the end
= 400 u - 50 u
= 350 u
= 350 x 6
= $2100
Answer(s): $2100
