The ratio of the number of $10-notes to $50-notes in Xandra's wallet was 1 : 7. Xandra exchanged 10 pieces of $50-notes for $10-notes. She then had an equal number of $10-notes and $50-notes. What was the total value of $10-notes and $50-notes in Xandra's wallet at first?
| |
$10-notes |
$50-notes |
| Before |
1 u |
7 u |
| Change |
+ 50 |
- 10 |
| After |
1 u + 50 |
7 u - 10 |
Value of 10 pieces of $50-notes
= 10 x 50
= $500
Number of $10-notes that Xandra exchanged for
= 500 ÷ 10
= 50
After the exchange, Xandra had an equal number of $10-notes and $50-notes.
7 u - 10 = 1 u + 50
7 u - 1 u = 50 + 10
6 u = 60
1 u = 60 ÷ 6 = 10
Number of $10-notes at first
= 1 u
= 10
Value of $10-notes at first
= 10 x 10
= $100
Number of $50-notes at first
= 7 u
= 7 x 10
= 70
Value of $50-notes at first
= 70 x 50
= $3500
Total value of $10-notes and $50-notes at first
= 100 + 3500
= $3600
Answer(s): $3600
