In a pouch of notes, the number of $5, $10 and $100 are in ratio of 7 : 1 : 6.
17 of the $5-notes and 7 $10-notes are taken out. The remaining notes are worth $2490. Find the difference between the value of $100-notes and $5-notes in the end.
| |
$5 |
$10 |
$100 |
| Before |
7 u |
1 u |
6 u |
| Change |
- 1 u |
- 7 |
|
| After |
6 u |
1 u - 7 |
6 u |
| |
$5 |
$10 |
$100 |
Total |
| Number |
6 u |
1 u - 7 |
6 u |
|
| Value |
5 |
10 |
100 |
|
| Total value |
30 u |
10 u - 70 |
600 u |
2490 |
Total value of the notes
= 30 u + 10 u - 70 + 600 u
= 640 u - 70
640 u - 70 = 2490
640 u = 2490 + 70
640 u = 2560
1 u = 2560 ÷ 640 = 4
Difference between the value of $100-notes and $5-notes in the end
= 600 u - 30 u
= 570 u
= 570 x 4
= $2280
Answer(s): $2280
