Esther had some $50-notes and some $10-notes.
710 of the notes were $50-notes and the rest were $10-notes. After Esther had spent $4080 worth of $10-notes and
67 of $50-notes, she had
211 of the notes left. Find the number of $10-notes Esther had left.
| |
$50-notes |
$10-notes |
Total |
Comparing $50-notes
and $10-notes
at first |
7x11 =
77 u |
3x11 =
33 u |
10x11 =
110 u |
| Before |
7x11 =
77 u |
|
11x10 =
110 u |
| Change |
- 6x11 =
- 66 u |
- 408 |
- 9x10 =
- 90 u |
| After |
1x11=
11 u |
33 u - 408 |
2x10 =
20 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 10 and 11 is 110.
The number of $50-notes is repeated.
Number of $10-notes
= 4080 ÷ 10
= 408
Total number of notes spent = 66 u + 408
66 u + 408 = 90 u
90 u - 66 u = 408
24 u = 408
1 u = 408 ÷ 24 = 17
Number of $10-notes that Esther had left
= 33 u - 408
= 33 x 17 - 408
= 153
Answer(s): 153
