Yoko had some $10-notes and some $1-notes.
512 of the notes were $10-notes and the rest were $1-notes. After Yoko had spent $351 worth of $1-notes and
15 of $10-notes, she had
38 of the notes left. Find the number of $1-notes Yoko had left.
| |
$10-notes |
$1-notes |
Total |
Comparing $10-notes
and $1-notes
at first |
5x2 =
10 u |
7x2 =
14 u |
12x2 =
24 u |
| Before |
5x2 =
10 u |
|
8x3 =
24 u |
| Change |
- 1x2 =
- 2 u |
- 351 |
- 5x3 =
- 15 u |
| After |
4x2=
8 u |
14 u - 351 |
3x3 =
9 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 12 and 8 is 24.
The number of $10-notes is repeated.
Number of $1-notes
= 351 ÷ 1
= 351
Total number of notes spent = 2 u + 351
2 u + 351 = 15 u
15 u - 2 u = 351
13 u = 351
1 u = 351 ÷ 13 = 27
Number of $1-notes that Yoko had left
= 14 u - 351
= 14 x 27 - 351
= 27
Answer(s): 27
