Rachel had some $10-notes and some $50-notes.
35 of the notes were $10-notes and the rest were $50-notes. After Rachel had spent $4400 worth of $50-notes and
13 of $10-notes, she had
811 of the notes left. Find the number of $50-notes Rachel had left.
| |
$10-notes |
$50-notes |
Total |
Comparing $10-notes
and $50-notes
at first |
3x11 =
33 u |
2x11 =
22 u |
5x11 =
55 u |
| Before |
3x11 =
33 u |
|
11x5 =
55 u |
| Change |
- 1x11 =
- 11 u |
- 88 |
- 3x5 =
- 15 u |
| After |
2x11=
22 u |
22 u - 88 |
8x5 =
40 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 $10-notes is repeated.
Number of $50-notes
= 4400 ÷ 50
= 88
Total number of notes spent = 11 u + 88
11 u + 88 = 15 u
15 u - 11 u = 88
4 u = 88
1 u = 88 ÷ 4 = 22
Number of $50-notes that Rachel had left
= 22 u - 88
= 22 x 22 - 88
= 396
Answer(s): 396
