Jaslyn had some $5-notes and some $1-notes.
512 of the notes were $5-notes and the rest were $1-notes. After Jaslyn had spent $108 worth of $1-notes and
25 of $5-notes, she had
13 of the notes left. Find the number of $1-notes Jaslyn had left.
| |
$5-notes |
$1-notes |
Total |
Comparing $5-notes
and $1-notes
at first |
5x1 =
5 u |
7x1 =
7 u |
12x1 =
12 u |
| Before |
5x1 =
5 u |
|
3x4 =
12 u |
| Change |
- 2x1 =
- 2 u |
- 108 |
- 2x4 =
- 8 u |
| After |
3x1=
3 u |
7 u - 108 |
1x4 =
4 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 12 and 3 is 12.
The number of $5-notes is repeated.
Number of $1-notes
= 108 ÷ 1
= 108
Total number of notes spent = 2 u + 108
2 u + 108 = 8 u
8 u - 2 u = 108
6 u = 108
1 u = 108 ÷ 6 = 18
Number of $1-notes that Jaslyn had left
= 7 u - 108
= 7 x 18 - 108
= 18
Answer(s): 18
