The ratio of the number of $2-notes to $10-notes in Barbara's wallet was 1 : 6. Barbara exchanged 5 pieces of $10-notes for $2-notes. She then had an equal number of $2-notes and $10-notes. What was the total value of $2-notes and $10-notes in Barbara's wallet at first?
| |
$2-notes |
$10-notes |
| Before |
1 u |
6 u |
| Change |
+ 25 |
- 5 |
| After |
1 u + 25 |
6 u - 5 |
Value of 5 pieces of $10-notes
= 5 x 10
= $50
Number of $2-notes that Barbara exchanged for
= 50 ÷ 2
= 25
After the exchange, Barbara had an equal number of $2-notes and $10-notes.
6 u - 5 = 1 u + 25
6 u - 1 u = 25 + 5
5 u = 30
1 u = 30 ÷ 5 = 6
Number of $2-notes at first
= 1 u
= 6
Value of $2-notes at first
= 6 x 2
= $12
Number of $10-notes at first
= 6 u
= 6 x 6
= 36
Value of $10-notes at first
= 36 x 10
= $360
Total value of $2-notes and $10-notes at first
= 12 + 360
= $372
Answer(s): $372
