Kimberly had some $10-notes and some $50-notes.
56 of the notes were $10-notes and the rest were $50-notes. After Kimberly had spent $4000 worth of $50-notes and
45 of $10-notes, she had
15 of the notes left. Find the number of $50-notes Kimberly had left.
| |
$10-notes |
$50-notes |
Total |
Comparing $10-notes
and $50-notes
at first |
5x5 =
25 u |
1x5 =
5 u |
6x5 =
30 u |
| Before |
5x5 =
25 u |
|
5x6 =
30 u |
| Change |
- 4x5 =
- 20 u |
- 80 |
- 4x6 =
- 24 u |
| After |
1x5=
5 u |
5 u - 80 |
1x6 =
6 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 6 and 5 is 30.
The number of $10-notes is repeated.
Number of $50-notes
= 4000 ÷ 50
= 80
Total number of notes spent = 20 u + 80
20 u + 80 = 24 u
24 u - 20 u = 80
4 u = 80
1 u = 80 ÷ 4 = 20
Number of $50-notes that Kimberly had left
= 5 u - 80
= 5 x 20 - 80
= 20
Answer(s): 20
