The ratio of the number of $10-notes to $50-notes in Eva's purse was 1 : 3. Eva exchanged 6 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 Eva's purse at first?
|
$10-notes |
$50-notes |
Before |
1 u |
3 u |
Change |
+ 30 |
- 6 |
After |
1 u + 30 |
3 u - 6 |
Value of 6 pieces of $50-notes
= 6 x 50
= $300
Number of $10-notes that Eva exchanged for
= 300 ÷ 10
= 30
After the exchange, Eva had an equal number of $10-notes and $50-notes.
3 u - 6 = 1 u + 30
3 u - 1 u = 30 + 6
2 u = 36
1 u = 36 ÷ 2 = 18
Number of $10-notes at first
= 1 u
= 18
Value of $10-notes at first
= 18 x 10
= $180
Number of $50-notes at first
= 3 u
= 3 x 18
= 54
Value of $50-notes at first
= 54 x 50
= $2700
Total value of $10-notes and $50-notes at first
= 180 + 2700
= $2880
Answer(s): $2880