In a pouch of notes, the number of $10, $20 and $100 are in ratio of 7 : 1 : 4.
27 of the $10-notes is taken out and another 3 $20-notes are added. The remaining notes are worth $4290. Find the difference between the value of $100-notes and $10-notes in the end.
| |
$10 |
$20 |
$100 |
| Before |
7 u |
1 u |
4 u |
| Change |
- 2 u |
+ 3 |
|
| After |
5 u |
1 u + 3 |
4 u |
| |
$10 |
$20 |
$100 |
Total |
| Number |
5 u |
1 u + 3 |
4 u |
|
| Value |
10 |
20 |
100 |
|
| Total value |
50 u |
20 u + 60 |
400 u |
4290 |
Total value of the notes
= 50 u + 20 u + 60 + 400 u
= 470 u + 60
470 u + 60 = 4290
470 u = 4290 - 60
470 u = 4230
1 u = 4230 ÷ 470 = 9
Difference between the value of $100-notes and $10-notes in the end
= 400 u - 50 u
= 350 u
= 350 x 9
= $3150
Answer(s): $3150
