Gillian had some $10-notes and some $2-notes.
57 of the-notes were $10-notes and the rest were $2-notes. After Gillian had spent $352 worth of $2-notes and
25 of $10-notes, she had
13 of the notes left. Find the number of $10-notes Gillian had left.
| |
$10-notes |
$2-notes |
Total |
Comparing $10-notes
and $2-notes
at first |
5x3 =
15 u |
2x3 =
6 u |
7x3 =
21 u |
| Before |
5x3 =
15 u |
|
3x7 =
21 u |
| Change |
- 2x3 =
- 6 u |
- 176 |
- 2x7 =
- 14 u |
| After |
3x3=
9 u |
6 u - 176 |
1x7 =
7 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 7 and 3 is 21.
The number of $10-notes is repeated.
Number of $2-notes
= 352 ÷ 2
= 176
Total number of notes spent = 6 u + 176
6 u + 176 = 14 u
14 u - 6 u = 176
8 u = 176
1 u = 176 ÷ 8 = 22
Number of $10-notes that Gillian had left
= 9 u
= 9 x 22
= 198
Answer(s): 198
