The ratio of the number of $10-notes to $20-notes in Nora's jar was 1 : 4. Nora exchanged 14 pieces of $20-notes for $10-notes. She then had an equal number of $10-notes and $20-notes. What was the total value of $10-notes and $20-notes in Nora's jar at first?
|
$10-notes |
$20-notes |
Before |
1 u |
4 u |
Change |
+ 28 |
- 14 |
After |
1 u + 28 |
4 u - 14 |
Value of 14 pieces of $20-notes
= 14 x 20
= $280
Number of $10-notes that Nora exchanged for
= 280 ÷ 10
= 28
After the exchange, Nora had an equal number of $10-notes and $20-notes.
4 u - 14 = 1 u + 28
4 u - 1 u = 28 + 14
3 u = 42
1 u = 42 ÷ 3 = 14
Number of $10-notes at first
= 1 u
= 14
Value of $10-notes at first
= 14 x 10
= $140
Number of $20-notes at first
= 4 u
= 4 x 14
= 56
Value of $20-notes at first
= 56 x 20
= $1120
Total value of $10-notes and $20-notes at first
= 140 + 1120
= $1260
Answer(s): $1260