Diana had some $50-notes and some $2-notes.
37 of the-notes were $50-notes and the rest were $2-notes. After Diana had spent $1710 worth of $2-notes and
13 of $50-notes, she had
311 of the notes left. Find the number of $50-notes Diana had left.
| |
$50-notes |
$2-notes |
Total |
Comparing $50-notes
and $2-notes
at first |
3x11 =
33 u |
4x11 =
44 u |
7x11 =
77 u |
| Before |
3x11 =
33 u |
|
11x7 =
77 u |
| Change |
- 1x11 =
- 11 u |
- 855 |
- 8x7 =
- 56 u |
| After |
2x11=
22 u |
44 u - 855 |
3x7 =
21 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 7 and 11 is 77.
The number of $50-notes is repeated.
Number of $2-notes
= 1710 ÷ 2
= 855
Total number of notes spent = 11 u + 855
11 u + 855 = 56 u
56 u - 11 u = 855
45 u = 855
1 u = 855 ÷ 45 = 19
Number of $50-notes that Diana had left
= 22 u
= 22 x 19
= 418
Answer(s): 418
