The ratio of the number of $10-notes to $50-notes in Dana's wallet was 1 : 4. Dana exchanged 4 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 Dana's wallet at first?
|
$10-notes |
$50-notes |
Before |
1 u |
4 u |
Change |
+ 20 |
- 4 |
After |
1 u + 20 |
4 u - 4 |
Value of 4 pieces of $50-notes
= 4 x 50
= $200
Number of $10-notes that Dana exchanged for
= 200 ÷ 10
= 20
After the exchange, Dana had an equal number of $10-notes and $50-notes.
4 u - 4 = 1 u + 20
4 u - 1 u = 20 + 4
3 u = 24
1 u = 24 ÷ 3 = 8
Number of $10-notes at first
= 1 u
= 8
Value of $10-notes at first
= 8 x 10
= $80
Number of $50-notes at first
= 4 u
= 4 x 8
= 32
Value of $50-notes at first
= 32 x 50
= $1600
Total value of $10-notes and $50-notes at first
= 80 + 1600
= $1680
Answer(s): $1680