The ratio of the number of $20-notes to $50-notes in Dana's handbag was 1 : 8. Dana exchanged 12 pieces of $50-notes for $20-notes. She then had an equal number of $20-notes and $50-notes. What was the total value of $20-notes and $50-notes in Dana's handbag at first?
|
$20-notes |
$50-notes |
Before |
1 u |
8 u |
Change |
+ 30 |
- 12 |
After |
1 u + 30 |
8 u - 12 |
Value of 12 pieces of $50-notes
= 12 x 50
= $600
Number of $20-notes that Dana exchanged for
= 600 ÷ 20
= 30
After the exchange, Dana had an equal number of $20-notes and $50-notes.
8 u - 12 = 1 u + 30
8 u - 1 u = 30 + 12
7 u = 42
1 u = 42 ÷ 7 = 6
Number of $20-notes at first
= 1 u
= 6
Value of $20-notes at first
= 6 x 20
= $120
Number of $50-notes at first
= 8 u
= 8 x 6
= 48
Value of $50-notes at first
= 48 x 50
= $2400
Total value of $20-notes and $50-notes at first
= 120 + 2400
= $2520
Answer(s): $2520