In a pouch of notes, the number of $5, $10 and $20 are in ratio of 6 : 5 : 1.
16 of the $5-notes and 2 $10-notes are taken out. The remaining notes are worth $550. Find the difference between the value of $20-notes and $5-notes in the end.
| |
$5 |
$10 |
$20 |
| Before |
6 u |
5 u |
1 u |
| Change |
- 1 u |
- 2 |
|
| After |
5 u |
5 u - 2 |
1 u |
| |
$5 |
$10 |
$20 |
Total |
| Number |
5 u |
5 u - 2 |
1 u |
|
| Value |
5 |
10 |
20 |
|
| Total value |
25 u |
50 u - 20 |
20 u |
550 |
Total value of the notes
= 25 u + 50 u - 20 + 20 u
= 95 u - 20
95 u - 20 = 550
95 u = 550 + 20
95 u = 570
1 u = 570 ÷ 95 = 6
Difference between the value of $20-notes and $5-notes in the end
= 20 u - 25 u
= -5 u
= -5 x 6
= $-30
Answer(s): $-30
