The ratio of the number of $2-notes to $10-notes in Ivory's wallet was 1 : 7. Ivory exchanged 13 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 Ivory's wallet at first?
|
$2-notes |
$10-notes |
Before |
1 u |
7 u |
Change |
+ 65 |
- 13 |
After |
1 u + 65 |
7 u - 13 |
Value of 13 pieces of $10-notes
= 13 x 10
= $130
Number of $2-notes that Ivory exchanged for
= 130 ÷ 2
= 65
After the exchange, Ivory had an equal number of $2-notes and $10-notes.
7 u - 13 = 1 u + 65
7 u - 1 u = 65 + 13
6 u = 78
1 u = 78 ÷ 6 = 13
Number of $2-notes at first
= 1 u
= 13
Value of $2-notes at first
= 13 x 2
= $26
Number of $10-notes at first
= 7 u
= 7 x 13
= 91
Value of $10-notes at first
= 91 x 10
= $910
Total value of $2-notes and $10-notes at first
= 26 + 910
= $936
Answer(s): $936