Kathy had an equal number of $20 and $1 notes. After spending 32 pieces of $1 and 10 pieces of $20 notes, the ratio of the $20 notes to $1 notes left was 3 : 1. Find the value of the notes left.
| |
$20 |
$1 |
| Before |
3 u + 10 |
1 u + 32 |
| Change |
- 10 |
- 32 |
| After |
3 u |
1 u |
Number of $20 notes at first = 3 u + 10
Number of $1 notes at first = 1 u + 32
The number of $20 and $1 notes at first is the same.
3 u + 10 = 1 u + 32
3 u - 1 u = 32 - 10
2 u = 22
1 u = 22 ÷ 2 = 11
Value of $20-notes left
= 3 u x 20
= 3 x 11 x 20
= $660
Value of $1-notes left
= 1 u x 1
= 1 x 11 x 1
= $11
Value of notes left
= 660 + 11
= $671
Answer(s): $671
