Emily had some $10-notes and some $5-notes.
511 of the notes were $10-notes and the rest were $5-notes. After Emily had spent $1050 worth of $5-notes and
45 of $10-notes, she had
13 of the notes left. Find the number of $5-notes Emily had left.
| |
$10-notes |
$5-notes |
Total |
Comparing $10-notes
and $5-notes
at first |
5x3 =
15 u |
6x3 =
18 u |
11x3 =
33 u |
| Before |
5x3 =
15 u |
|
3x11 =
33 u |
| Change |
- 4x3 =
- 12 u |
- 210 |
- 2x11 =
- 22 u |
| After |
1x3=
3 u |
18 u - 210 |
1x11 =
11 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 $10-notes is repeated.
Number of $5-notes
= 1050 ÷ 5
= 210
Total number of notes spent = 12 u + 210
12 u + 210 = 22 u
22 u - 12 u = 210
10 u = 210
1 u = 210 ÷ 10 = 21
Number of $5-notes that Emily had left
= 18 u - 210
= 18 x 21 - 210
= 168
Answer(s): 168
