In a pouch of notes, the number of $10, $20 and $50 are in ratio of 4 : 7 : 1.
14 of the $10-notes is taken out and another 4 $20-notes are added. The remaining notes are worth $960. Find the difference between the value of $50-notes and $10-notes in the end.
| |
$10 |
$20 |
$50 |
| Before |
4 u |
7 u |
1 u |
| Change |
- 1 u |
+ 4 |
|
| After |
3 u |
7 u + 4 |
1 u |
| |
$10 |
$20 |
$50 |
Total |
| Number |
3 u |
7 u + 4 |
1 u |
|
| Value |
10 |
20 |
50 |
|
| Total value |
30 u |
140 u + 80 |
50 u |
960 |
Total value of the notes
= 30 u + 140 u + 80 + 50 u
= 220 u + 80
220 u + 80 = 960
220 u = 960 - 80
220 u = 880
1 u = 880 ÷ 220 = 4
Difference between the value of $50-notes and $10-notes in the end
= 50 u - 30 u
= 20 u
= 20 x 4
= $80
Answer(s): $80
