Xuan had an equal number of $20 and $100 notes. After spending 19 pieces of $100 and 11 pieces of $20 notes, the ratio of the $20 notes to $100 notes left was 7 : 3. Find the value of the notes left.
| |
$20 |
$100 |
| Before |
7 u + 11 |
3 u + 19 |
| Change |
- 11 |
- 19 |
| After |
7 u |
3 u |
Number of $20 notes at first = 7 u + 11
Number of $100 notes at first = 3 u + 19
The number of $20 and $100 notes at first is the same.
7 u + 11 = 3 u + 19
7 u - 3 u = 19 - 11
4 u = 8
1 u = 8 ÷ 4 = 2
Value of $20-notes left
= 7 u x 20
= 7 x 2 x 20
= $280
Value of $100-notes left
= 3 u x 100
= 3 x 2 x 100
= $600
Value of notes left
= 280 + 600
= $880
Answer(s): $880
