Joelle had some $100-notes and some $2-notes.
811 of the notes were $100-notes and the rest were $2-notes. After Joelle had spent $288 worth of $2-notes and
18 of $100-notes, she had
45 of the notes left. Find the number of $2-notes Joelle had left.
| |
$100-notes |
$2-notes |
Total |
Comparing $100-notes
and $2-notes
at first |
8x5 =
40 u |
3x5 =
15 u |
11x5 =
55 u |
| Before |
8x5 =
40 u |
|
5x11 =
55 u |
| Change |
- 1x5 =
- 5 u |
- 144 |
- 1x11 =
- 11 u |
| After |
7x5=
35 u |
15 u - 144 |
4x11 =
44 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 11 and 5 is 55.
The number of $100-notes is repeated.
Number of $2-notes
= 288 ÷ 2
= 144
Total number of notes spent = 5 u + 144
5 u + 144 = 11 u
11 u - 5 u = 144
6 u = 144
1 u = 144 ÷ 6 = 24
Number of $2-notes that Joelle had left
= 15 u - 144
= 15 x 24 - 144
= 216
Answer(s): 216
