Linda had some $2-notes and some $50-notes.
38 of the notes were $2-notes and the rest were $50-notes. After Linda had spent $7650 worth of $50-notes and
13 of $2-notes, she had
57 of the notes left. Find the number of $50-notes Linda had left.
| |
$2-notes |
$50-notes |
Total |
Comparing $2-notes
and $50-notes
at first |
3x7 =
21 u |
5x7 =
35 u |
8x7 =
56 u |
| Before |
3x7 =
21 u |
|
7x8 =
56 u |
| Change |
- 1x7 =
- 7 u |
- 153 |
- 2x8 =
- 16 u |
| After |
2x7=
14 u |
35 u - 153 |
5x8 =
40 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 8 and 7 is 56.
The number of $2-notes is repeated.
Number of $50-notes
= 7650 ÷ 50
= 153
Total number of notes spent = 7 u + 153
7 u + 153 = 16 u
16 u - 7 u = 153
9 u = 153
1 u = 153 ÷ 9 = 17
Number of $50-notes that Linda had left
= 35 u - 153
= 35 x 17 - 153
= 442
Answer(s): 442
