Risa had an equal number of $50 and $100 notes. After spending 18 pieces of $100 and 15 pieces of $50 notes, the ratio of the $50 notes to $100 notes left was 8 : 5. Find the value of the notes left.
| |
$50 |
$100 |
| Before |
8 u + 15 |
5 u + 18 |
| Change |
- 15 |
- 18 |
| After |
8 u |
5 u |
Number of $50 notes at first = 8 u + 15
Number of $100 notes at first = 5 u + 18
The number of $50 and $100 notes at first is the same.
8 u + 15 = 5 u + 18
8 u - 5 u = 18 - 15
3 u = 3
1 u = 3 ÷ 3 = 1
Value of $50-notes left
= 8 u x 50
= 8 x 1 x 50
= $400
Value of $100-notes left
= 5 u x 100
= 5 x 1 x 100
= $500
Value of notes left
= 400 + 500
= $900
Answer(s): $900
