In a bag of notes, the number of $10, $20 and $100 are in ratio of 7 : 3 : 1.
47 of the $10-notes and 6 $20-notes are taken out. The remaining notes are worth $1210. Find the difference between the value of $100-notes and $10-notes in the end.
| |
$10 |
$20 |
$100 |
| Before |
7 u |
3 u |
1 u |
| Change |
- 4 u |
- 6 |
|
| After |
3 u |
3 u - 6 |
1 u |
| |
$10 |
$20 |
$100 |
Total |
| Number |
3 u |
3 u - 6 |
1 u |
|
| Value |
10 |
20 |
100 |
|
| Total value |
30 u |
60 u - 120 |
100 u |
1210 |
Total value of the notes
= 30 u + 60 u - 120 + 100 u
= 190 u - 120
190 u - 120 = 1210
190 u = 1210 + 120
190 u = 1330
1 u = 1330 ÷ 190 = 7
Difference between the value of $100-notes and $10-notes in the end
= 100 u - 30 u
= 70 u
= 70 x 7
= $490
Answer(s): $490
