The ratio of the number of $2-notes to $10-notes in Pamela's purse was 1 : 3. Pamela 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 Pamela's purse at first?
|
$2-notes |
$10-notes |
Before |
1 u |
3 u |
Change |
+ 25 |
- 5 |
After |
1 u + 25 |
3 u - 5 |
Value of 5 pieces of $10-notes
= 5 x 10
= $50
Number of $2-notes that Pamela exchanged for
= 50 ÷ 2
= 25
After the exchange, Pamela had an equal number of $2-notes and $10-notes.
3 u - 5 = 1 u + 25
3 u - 1 u = 25 + 5
2 u = 30
1 u = 30 ÷ 2 = 15
Number of $2-notes at first
= 1 u
= 15
Value of $2-notes at first
= 15 x 2
= $30
Number of $10-notes at first
= 3 u
= 3 x 15
= 45
Value of $10-notes at first
= 45 x 10
= $450
Total value of $2-notes and $10-notes at first
= 30 + 450
= $480
Answer(s): $480