Raeann had some $1-notes and some $2-notes.
711 of the notes were $1-notes and the rest were $2-notes. After Raeann had spent $1380 worth of $2-notes and
67 of $1-notes, she had
29 of the notes left. Find the number of $2-notes Raeann had left.
| |
$1-notes |
$2-notes |
Total |
Comparing $1-notes
and $2-notes
at first |
7x9 =
63 u |
4x9 =
36 u |
11x9 =
99 u |
| Before |
7x9 =
63 u |
|
9x11 =
99 u |
| Change |
- 6x9 =
- 54 u |
- 690 |
- 7x11 =
- 77 u |
| After |
1x9=
9 u |
36 u - 690 |
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 9 is 99.
The number of $1-notes is repeated.
Number of $2-notes
= 1380 ÷ 2
= 690
Total number of notes spent = 54 u + 690
54 u + 690 = 77 u
77 u - 54 u = 690
23 u = 690
1 u = 690 ÷ 23 = 30
Number of $2-notes that Raeann had left
= 36 u - 690
= 36 x 30 - 690
= 390
Answer(s): 390
