Abi had some $1-notes and some $100-notes.
49 of the notes were $1-notes and the rest were $100-notes. After Abi had spent $3200 worth of $100-notes and
14 of $1-notes, she had
23 of the notes left. Find the number of $100-notes Abi had left.
| |
$1-notes |
$100-notes |
Total |
Comparing $1-notes
and $100-notes
at first |
4x1 =
4 u |
5x1 =
5 u |
9x1 =
9 u |
| Before |
4x1 =
4 u |
|
3x3 =
9 u |
| Change |
- 1x1 =
- 1 u |
- 32 |
- 1x3 =
- 3 u |
| After |
3x1=
3 u |
5 u - 32 |
2x3 =
6 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 9 and 3 is 9.
The number of $1-notes is repeated.
Number of $100-notes
= 3200 ÷ 100
= 32
Total number of notes spent = 1 u + 32
1 u + 32 = 3 u
3 u - 1 u = 32
2 u = 32
1 u = 32 ÷ 2 = 16
Number of $100-notes that Abi had left
= 5 u - 32
= 5 x 16 - 32
= 48
Answer(s): 48
