The ratio of the number of $5-notes to $20-notes in Tina's bag was 1 : 6. Tina exchanged 5 pieces of $20-notes for $5-notes. She then had an equal number of $5-notes and $20-notes. What was the total value of $5-notes and $20-notes in Tina's bag at first?
| |
$5-notes |
$20-notes |
| Before |
1 u |
6 u |
| Change |
+ 20 |
- 5 |
| After |
1 u + 20 |
6 u - 5 |
Value of 5 pieces of $20-notes
= 5 x 20
= $100
Number of $5-notes that Tina exchanged for
= 100 ÷ 5
= 20
After the exchange, Tina had an equal number of $5-notes and $20-notes.
6 u - 5 = 1 u + 20
6 u - 1 u = 20 + 5
5 u = 25
1 u = 25 ÷ 5 = 5
Number of $5-notes at first
= 1 u
= 5
Value of $5-notes at first
= 5 x 5
= $25
Number of $20-notes at first
= 6 u
= 6 x 5
= 30
Value of $20-notes at first
= 30 x 20
= $600
Total value of $5-notes and $20-notes at first
= 25 + 600
= $625
Answer(s): $625
