The ratio of the number of $2-notes to $10-notes in Eva's jar was 1 : 5. Eva exchanged 6 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 Eva's jar at first?
|
$2-notes |
$10-notes |
Before |
1 u |
5 u |
Change |
+ 30 |
- 6 |
After |
1 u + 30 |
5 u - 6 |
Value of 6 pieces of $10-notes
= 6 x 10
= $60
Number of $2-notes that Eva exchanged for
= 60 ÷ 2
= 30
After the exchange, Eva had an equal number of $2-notes and $10-notes.
5 u - 6 = 1 u + 30
5 u - 1 u = 30 + 6
4 u = 36
1 u = 36 ÷ 4 = 9
Number of $2-notes at first
= 1 u
= 9
Value of $2-notes at first
= 9 x 2
= $18
Number of $10-notes at first
= 5 u
= 5 x 9
= 45
Value of $10-notes at first
= 45 x 10
= $450
Total value of $2-notes and $10-notes at first
= 18 + 450
= $468
Answer(s): $468