Lucy had an equal number of $100 and $5 notes. After spending 45 pieces of $5 and 42 pieces of $100 notes, the ratio of the $100 notes to $5 notes left was 5 : 2. Find the value of the notes left.
| |
$100 |
$5 |
| Before |
5 u + 42 |
2 u + 45 |
| Change |
- 42 |
- 45 |
| After |
5 u |
2 u |
Number of $100 notes at first = 5 u + 42
Number of $5 notes at first = 2 u + 45
The number of $100 and $5 notes at first is the same.
5 u + 42 = 2 u + 45
5 u - 2 u = 45 - 42
3 u = 3
1 u = 3 ÷ 3 = 1
Value of $100-notes left
= 5 u x 100
= 5 x 1 x 100
= $500
Value of $5-notes left
= 2 u x 5
= 2 x 1 x 5
= $10
Value of notes left
= 500 + 10
= $510
Answer(s): $510
