In a box of notes, the number of $10, $20 and $100 are in ratio of 5 : 4 : 2.
15 of the $10-notes is taken out and another 14 $20-notes are added. The remaining notes are worth $1240. Find the difference between the value of $100-notes and $10-notes in the end.
| |
$10 |
$20 |
$100 |
| Before |
5 u |
4 u |
2 u |
| Change |
- 1 u |
+ 14 |
|
| After |
4 u |
4 u + 14 |
2 u |
| |
$10 |
$20 |
$100 |
Total |
| Number |
4 u |
4 u + 14 |
2 u |
|
| Value |
10 |
20 |
100 |
|
| Total value |
40 u |
80 u + 280 |
200 u |
1240 |
Total value of the notes
= 40 u + 80 u + 280 + 200 u
= 320 u + 280
320 u + 280 = 1240
320 u = 1240 - 280
320 u = 960
1 u = 960 ÷ 320 = 3
Difference between the value of $100-notes and $10-notes in the end
= 200 u - 40 u
= 160 u
= 160 x 3
= $480
Answer(s): $480
