Joelle had an equal number of $10 and $2 notes. After spending 30 pieces of $2 and 18 pieces of $10 notes, the ratio of the $10 notes to $2 notes left was 7 : 1. Find the value of the notes left.
| |
$10 |
$2 |
| Before |
7 u + 18 |
1 u + 30 |
| Change |
- 18 |
- 30 |
| After |
7 u |
1 u |
Number of $10 notes at first = 7 u + 18
Number of $2 notes at first = 1 u + 30
The number of $10 and $2 notes at first is the same.
7 u + 18 = 1 u + 30
7 u - 1 u = 30 - 18
6 u = 12
1 u = 12 ÷ 6 = 2
Value of $10-notes left
= 7 u x 10
= 7 x 2 x 10
= $140
Value of $2-notes left
= 1 u x 2
= 1 x 2 x 2
= $4
Value of notes left
= 140 + 4
= $144
Answer(s): $144
