In a pouch of notes, the number of $10, $20 and $50 are in ratio of 5 : 1 : 2.
25 of the $10-notes is taken out and another 12 $20-notes are added. The remaining notes are worth $1590. Find the difference between the value of $50-notes and $10-notes in the end.
| |
$10 |
$20 |
$50 |
| Before |
5 u |
1 u |
2 u |
| Change |
- 2 u |
+ 12 |
|
| After |
3 u |
1 u + 12 |
2 u |
| |
$10 |
$20 |
$50 |
Total |
| Number |
3 u |
1 u + 12 |
2 u |
|
| Value |
10 |
20 |
50 |
|
| Total value |
30 u |
20 u + 240 |
100 u |
1590 |
Total value of the notes
= 30 u + 20 u + 240 + 100 u
= 150 u + 240
150 u + 240 = 1590
150 u = 1590 - 240
150 u = 1350
1 u = 1350 ÷ 150 = 9
Difference between the value of $50-notes and $10-notes in the end
= 100 u - 30 u
= 70 u
= 70 x 9
= $630
Answer(s): $630
