In a pouch of notes, the number of $2, $5 and $20 are in ratio of 7 : 5 : 1.
27 of the $2-notes and 4 $5-notes are taken out. The remaining notes are worth $145. Find the difference between the value of $20-notes and $2-notes in the end.
| |
$2 |
$5 |
$20 |
| Before |
7 u |
5 u |
1 u |
| Change |
- 2 u |
- 4 |
|
| After |
5 u |
5 u - 4 |
1 u |
| |
$2 |
$5 |
$20 |
Total |
| Number |
5 u |
5 u - 4 |
1 u |
|
| Value |
2 |
5 |
20 |
|
| Total value |
10 u |
25 u - 20 |
20 u |
145 |
Total value of the notes
= 10 u + 25 u - 20 + 20 u
= 55 u - 20
55 u - 20 = 145
55 u = 145 + 20
55 u = 165
1 u = 165 ÷ 55 = 3
Difference between the value of $20-notes and $2-notes in the end
= 20 u - 10 u
= 10 u
= 10 x 3
= $30
Answer(s): $30
