The ratio of the number of $5-notes to $50-notes in Diana's wallet was 1 : 7. Diana exchanged 12 pieces of $50-notes for $5-notes. She then had an equal number of $5-notes and $50-notes. What was the total value of $5-notes and $50-notes in Diana's wallet at first?
|
$5-notes |
$50-notes |
Before |
1 u |
7 u |
Change |
+ 120 |
- 12 |
After |
1 u + 120 |
7 u - 12 |
Value of 12 pieces of $50-notes
= 12 x 50
= $600
Number of $5-notes that Diana exchanged for
= 600 ÷ 5
= 120
After the exchange, Diana had an equal number of $5-notes and $50-notes.
7 u - 12 = 1 u + 120
7 u - 1 u = 120 + 12
6 u = 132
1 u = 132 ÷ 6 = 22
Number of $5-notes at first
= 1 u
= 22
Value of $5-notes at first
= 22 x 5
= $110
Number of $50-notes at first
= 7 u
= 7 x 22
= 154
Value of $50-notes at first
= 154 x 50
= $7700
Total value of $5-notes and $50-notes at first
= 110 + 7700
= $7810
Answer(s): $7810