The ratio of the number of $10-notes to $50-notes in Xuan's bag was 1 : 7. Xuan exchanged 11 pieces of $50-notes for $10-notes. She then had an equal number of $10-notes and $50-notes. What was the total value of $10-notes and $50-notes in Xuan's bag at first?
| |
$10-notes |
$50-notes |
| Before |
1 u |
7 u |
| Change |
+ 55 |
- 11 |
| After |
1 u + 55 |
7 u - 11 |
Value of 11 pieces of $50-notes
= 11 x 50
= $550
Number of $10-notes that Xuan exchanged for
= 550 ÷ 10
= 55
After the exchange, Xuan had an equal number of $10-notes and $50-notes.
7 u - 11 = 1 u + 55
7 u - 1 u = 55 + 11
6 u = 66
1 u = 66 ÷ 6 = 11
Number of $10-notes at first
= 1 u
= 11
Value of $10-notes at first
= 11 x 10
= $110
Number of $50-notes at first
= 7 u
= 7 x 11
= 77
Value of $50-notes at first
= 77 x 50
= $3850
Total value of $10-notes and $50-notes at first
= 110 + 3850
= $3960
Answer(s): $3960
