Emma had some $5-notes and some $50-notes.
811 of the-notes were $5-notes and the rest were $50-notes. After Emma had spent $2700 worth of $50-notes and
38 of $5-notes, she had
23 of the notes left. Find the number of $5-notes Emma had left.
| |
$5-notes |
$50-notes |
Total |
Comparing $5-notes
and $50-notes
at first |
8x3 =
24 u |
3x3 =
9 u |
11x3 =
33 u |
| Before |
8x3 =
24 u |
|
3x11 =
33 u |
| Change |
- 3x3 =
- 9 u |
- 54 |
- 1x11 =
- 11 u |
| After |
5x3=
15 u |
9 u - 54 |
2x11 =
22 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 11 and 3 is 33.
The number of $5-notes is repeated.
Number of $50-notes
= 2700 ÷ 50
= 54
Total number of notes spent = 9 u + 54
9 u + 54 = 11 u
11 u - 9 u = 54
2 u = 54
1 u = 54 ÷ 2 = 27
Number of $5-notes that Emma had left
= 15 u
= 15 x 27
= 405
Answer(s): 405
