Raeann had some $10-notes and some $2-notes.
79 of the notes were $10-notes and the rest were $2-notes. After Raeann had spent $240 worth of $2-notes and
17 of $10-notes, she had
34 of the notes left. Find the number of $2-notes Raeann had left.
| |
$10-notes |
$2-notes |
Total |
Comparing $10-notes
and $2-notes
at first |
7x4 =
28 u |
2x4 =
8 u |
9x4 =
36 u |
| Before |
7x4 =
28 u |
|
4x9 =
36 u |
| Change |
- 1x4 =
- 4 u |
- 120 |
- 1x9 =
- 9 u |
| After |
6x4=
24 u |
8 u - 120 |
3x9 =
27 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 9 and 4 is 36.
The number of $10-notes is repeated.
Number of $2-notes
= 240 ÷ 2
= 120
Total number of notes spent = 4 u + 120
4 u + 120 = 9 u
9 u - 4 u = 120
5 u = 120
1 u = 120 ÷ 5 = 24
Number of $2-notes that Raeann had left
= 8 u - 120
= 8 x 24 - 120
= 72
Answer(s): 72
