The ratio of the number of $2-notes to $10-notes in Pamela's purse was 1 : 7. Pamela exchanged 7 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 Pamela's purse at first?
|
$2-notes |
$10-notes |
Before |
1 u |
7 u |
Change |
+ 35 |
- 7 |
After |
1 u + 35 |
7 u - 7 |
Value of 7 pieces of $10-notes
= 7 x 10
= $70
Number of $2-notes that Pamela exchanged for
= 70 ÷ 2
= 35
After the exchange, Pamela had an equal number of $2-notes and $10-notes.
7 u - 7 = 1 u + 35
7 u - 1 u = 35 + 7
6 u = 42
1 u = 42 ÷ 6 = 7
Number of $2-notes at first
= 1 u
= 7
Value of $2-notes at first
= 7 x 2
= $14
Number of $10-notes at first
= 7 u
= 7 x 7
= 49
Value of $10-notes at first
= 49 x 10
= $490
Total value of $2-notes and $10-notes at first
= 14 + 490
= $504
Answer(s): $504