Cathy had an equal number of $10 and $20 notes. After spending 48 pieces of $20 and 13 pieces of $10 notes, the ratio of the $10 notes to $20 notes left was 8 : 1. Find the value of the notes left.
| |
$10 |
$20 |
| Before |
8 u + 13 |
1 u + 48 |
| Change |
- 13 |
- 48 |
| After |
8 u |
1 u |
Number of $10 notes at first = 8 u + 13
Number of $20 notes at first = 1 u + 48
The number of $10 and $20 notes at first is the same.
8 u + 13 = 1 u + 48
8 u - 1 u = 48 - 13
7 u = 35
1 u = 35 ÷ 7 = 5
Value of $10-notes left
= 8 u x 10
= 8 x 5 x 10
= $400
Value of $20-notes left
= 1 u x 20
= 1 x 5 x 20
= $100
Value of notes left
= 400 + 100
= $500
Answer(s): $500
