Xandra had some $100-notes and some $2-notes.
45 of the notes were $100-notes and the rest were $2-notes. After Xandra had spent $100 worth of $2-notes and
34 of $100-notes, she had
411 of the notes left. Find the number of $2-notes Xandra had left.
| |
$100-notes |
$2-notes |
Total |
Comparing $100-notes
and $2-notes
at first |
4x11 =
44 u |
1x11 =
11 u |
5x11 =
55 u |
| Before |
4x11 =
44 u |
|
11x5 =
55 u |
| Change |
- 3x11 =
- 33 u |
- 50 |
- 7x5 =
- 35 u |
| After |
1x11=
11 u |
11 u - 50 |
4x5 =
20 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 5 and 11 is 55.
The number of $100-notes is repeated.
Number of $2-notes
= 100 ÷ 2
= 50
Total number of notes spent = 33 u + 50
33 u + 50 = 35 u
35 u - 33 u = 50
2 u = 50
1 u = 50 ÷ 2 = 25
Number of $2-notes that Xandra had left
= 11 u - 50
= 11 x 25 - 50
= 225
Answer(s): 225
