Opal had some $10-notes and some $50-notes.
56 of the-notes were $10-notes and the rest were $50-notes. After Opal had spent $1600 worth of $50-notes and
45 of $10-notes, she had
29 of the notes left. Find the number of $10-notes Opal had left.
| |
$10-notes |
$50-notes |
Total |
Comparing $10-notes
and $50-notes
at first |
5x3 =
15 u |
1x3 =
3 u |
6x3 =
18 u |
| Before |
5x3 =
15 u |
|
9x2 =
18 u |
| Change |
- 4x3 =
- 12 u |
- 32 |
- 7x2 =
- 14 u |
| After |
1x3=
3 u |
3 u - 32 |
2x2 =
4 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 6 and 9 is 18.
The number of $10-notes is repeated.
Number of $50-notes
= 1600 ÷ 50
= 32
Total number of notes spent = 12 u + 32
12 u + 32 = 14 u
14 u - 12 u = 32
2 u = 32
1 u = 32 ÷ 2 = 16
Number of $10-notes that Opal had left
= 3 u
= 3 x 16
= 48
Answer(s): 48
