Vanessa had some $50-notes and some $1-notes.
910 of the-notes were $50-notes and the rest were $1-notes. After Vanessa had spent $160 worth of $1-notes and
49 of $50-notes, she had
13 of the notes left. Find the number of $50-notes Vanessa had left.
| |
$50-notes |
$1-notes |
Total |
Comparing $50-notes
and $1-notes
at first |
9x3 =
27 u |
1x3 =
3 u |
10x3 =
30 u |
| Before |
9x3 =
27 u |
|
3x10 =
30 u |
| Change |
- 4x3 =
- 12 u |
- 160 |
- 2x10 =
- 20 u |
| After |
5x3=
15 u |
3 u - 160 |
1x10 =
10 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 10 and 3 is 30.
The number of $50-notes is repeated.
Number of $1-notes
= 160 ÷ 1
= 160
Total number of notes spent = 12 u + 160
12 u + 160 = 20 u
20 u - 12 u = 160
8 u = 160
1 u = 160 ÷ 8 = 20
Number of $50-notes that Vanessa had left
= 15 u
= 15 x 20
= 300
Answer(s): 300
