In a pouch of notes, the number of $20, $50 and $100 are in ratio of 5 : 2 : 4.
35 of the $20-notes is taken out and another 15 $50-notes are added. The remaining notes are worth $2910. Find the difference between the value of $100-notes and $20-notes in the end.
| |
$20 |
$50 |
$100 |
| Before |
5 u |
2 u |
4 u |
| Change |
- 3 u |
+ 15 |
|
| After |
2 u |
2 u + 15 |
4 u |
| |
$20 |
$50 |
$100 |
Total |
| Number |
2 u |
2 u + 15 |
4 u |
|
| Value |
20 |
50 |
100 |
|
| Total value |
40 u |
100 u + 750 |
400 u |
2910 |
Total value of the notes
= 40 u + 100 u + 750 + 400 u
= 540 u + 750
540 u + 750 = 2910
540 u = 2910 - 750
540 u = 2160
1 u = 2160 ÷ 540 = 4
Difference between the value of $100-notes and $20-notes in the end
= 400 u - 40 u
= 360 u
= 360 x 4
= $1440
Answer(s): $1440
