The ratio of the number of $2-notes to $10-notes in Jen's bag was 1 : 8. Jen 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 Jen's bag at first?
|
$2-notes |
$10-notes |
Before |
1 u |
8 u |
Change |
+ 35 |
- 7 |
After |
1 u + 35 |
8 u - 7 |
Value of 7 pieces of $10-notes
= 7 x 10
= $70
Number of $2-notes that Jen exchanged for
= 70 ÷ 2
= 35
After the exchange, Jen had an equal number of $2-notes and $10-notes.
8 u - 7 = 1 u + 35
8 u - 1 u = 35 + 7
7 u = 42
1 u = 42 ÷ 7 = 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
= 8 u
= 8 x 6
= 48
Value of $10-notes at first
= 48 x 10
= $480
Total value of $2-notes and $10-notes at first
= 12 + 480
= $492
Answer(s): $492