The ratio of the number of $5-notes to $10-notes in Julie's bag was 1 : 4. Julie exchanged 15 pieces of $10-notes for $5-notes. She then had an equal number of $5-notes and $10-notes. What was the total value of $5-notes and $10-notes in Julie's bag at first?
|
$5-notes |
$10-notes |
Before |
1 u |
4 u |
Change |
+ 30 |
- 15 |
After |
1 u + 30 |
4 u - 15 |
Value of 15 pieces of $10-notes
= 15 x 10
= $150
Number of $5-notes that Julie exchanged for
= 150 ÷ 5
= 30
After the exchange, Julie had an equal number of $5-notes and $10-notes.
4 u - 15 = 1 u + 30
4 u - 1 u = 30 + 15
3 u = 45
1 u = 45 ÷ 3 = 15
Number of $5-notes at first
= 1 u
= 15
Value of $5-notes at first
= 15 x 5
= $75
Number of $10-notes at first
= 4 u
= 4 x 15
= 60
Value of $10-notes at first
= 60 x 10
= $600
Total value of $5-notes and $10-notes at first
= 75 + 600
= $675
Answer(s): $675