Penelope had some $10-notes and some $2-notes.
49 of the-notes were $10-notes and the rest were $2-notes. After Penelope had spent $2592 worth of $2-notes and
34 of $10-notes, she had
211 of the notes left. Find the number of $10-notes Penelope had left.
| |
$10-notes |
$2-notes |
Total |
Comparing $10-notes
and $2-notes
at first |
4x11 =
44 u |
5x11 =
55 u |
9x11 =
99 u |
| Before |
4x11 =
44 u |
|
11x9 =
99 u |
| Change |
- 3x11 =
- 33 u |
- 1296 |
- 9x9 =
- 81 u |
| After |
1x11=
11 u |
55 u - 1296 |
2x9 =
18 u |
The total number of notes at first is the repeated. Make the total number of notes the same. LCM of 9 and 11 is 99.
The number of $10-notes is repeated.
Number of $2-notes
= 2592 ÷ 2
= 1296
Total number of notes spent = 33 u + 1296
33 u + 1296 = 81 u
81 u - 33 u = 1296
48 u = 1296
1 u = 1296 ÷ 48 = 27
Number of $10-notes that Penelope had left
= 11 u
= 11 x 27
= 297
Answer(s): 297
