Jade had some $50-notes and some $1-notes.
310 of the-notes were $50-notes and the rest were $1-notes. After Jade had spent $69 worth of $1-notes and
13 of $50-notes, she had
67 of the notes left. Find the number of $50-notes Jade had left.
| |
$50-notes |
$1-notes |
Total |
Comparing $50-notes
and $1-notes
at first |
3x7 =
21 u |
7x7 =
49 u |
10x7 =
70 u |
| Before |
3x7 =
21 u |
|
7x10 =
70 u |
| Change |
- 1x7 =
- 7 u |
- 69 |
- 1x10 =
- 10 u |
| After |
2x7=
14 u |
49 u - 69 |
6x10 =
60 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 10 and 7 is 70.
The number of $50-notes is repeated.
Number of $1-notes
= 69 ÷ 1
= 69
Total number of notes spent = 7 u + 69
7 u + 69 = 10 u
10 u - 7 u = 69
3 u = 69
1 u = 69 ÷ 3 = 23
Number of $50-notes that Jade had left
= 14 u
= 14 x 23
= 322
Answer(s): 322
