Lynn had some $100-notes and some $2-notes.
56 of the-notes were $100-notes and the rest were $2-notes. After Lynn had spent $140 worth of $2-notes and
45 of $100-notes, she had
110 of the notes left. Find the number of $100-notes Lynn had left.
| |
$100-notes |
$2-notes |
Total |
Comparing $100-notes
and $2-notes
at first |
5x5 =
25 u |
1x5 =
5 u |
6x5 =
30 u |
| Before |
5x5 =
25 u |
|
10x3 =
30 u |
| Change |
- 4x5 =
- 20 u |
- 70 |
- 9x3 =
- 27 u |
| After |
1x5=
5 u |
5 u - 70 |
1x3 =
3 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 6 and 10 is 30.
The number of $100-notes is repeated.
Number of $2-notes
= 140 ÷ 2
= 70
Total number of notes spent = 20 u + 70
20 u + 70 = 27 u
27 u - 20 u = 70
7 u = 70
1 u = 70 ÷ 7 = 10
Number of $100-notes that Lynn had left
= 5 u
= 5 x 10
= 50
Answer(s): 50
