Barbara spent
23 of her money on 11 files and 7 notebooks. The cost of each notebook is 3 times the cost of each file. She bought some more files with
12 of her remaining money. How many files did Barbara buy altogether?
| 11 files + 7 notebooks |
Remaining
amount |
Total
amount |
| 2 p = 32 u |
1 p = 16 u |
3 p |
11
files |
7
notebooks |
More files |
Left |
|
| |
|
1 |
1 |
|
| 11 u |
21 u |
8 u |
|
|
Cost of 1 file = 1 u
Cost of 1 notebook = 3 u
Cost of 11 files = 11 x 1 u = 11 u
Cost of 7 notebooks = 7 x 3 u = 21 u
Cost of 11 files + 7 notebooks
= 11 u + 21 u
= 32 u
2 p = 32 u
1 p = 32 u ÷ 2 = 16 u
Amount of remaining money that Barbara spent on buying more files
=
12 x 16 u
= 8 u
Number of files that Barbara bought with
12 of her remaining money
= 8 u ÷ 1 u
= 8
Total number of files that Barbara bought
= 11 + 8
= 19
Answer(s): 19
