Dana had some $1-notes and some $2-notes.
710 of the-notes were $1-notes and the rest were $2-notes. After Dana had spent $1104 worth of $2-notes and
37 of $1-notes, she had
18 of the notes left. Find the number of $1-notes Dana had left.
| |
$1-notes |
$2-notes |
Total |
Comparing $1-notes
and $2-notes
at first |
7x4 =
28 u |
3x4 =
12 u |
10x4 =
40 u |
| Before |
7x4 =
28 u |
|
8x5 =
40 u |
| Change |
- 3x4 =
- 12 u |
- 552 |
- 7x5 =
- 35 u |
| After |
4x4=
16 u |
12 u - 552 |
1x5 =
5 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 10 and 8 is 40.
The number of $1-notes is repeated.
Number of $2-notes
= 1104 ÷ 2
= 552
Total number of notes spent = 12 u + 552
12 u + 552 = 35 u
35 u - 12 u = 552
23 u = 552
1 u = 552 ÷ 23 = 24
Number of $1-notes that Dana had left
= 16 u
= 16 x 24
= 384
Answer(s): 384
