Last week, Mark had a total of 191 white and yellow files. Two weeks later, he sold
23 of all the white files and bought another 13 yellow files. Now he has the same number of white and yellow files. How many files does he have in the end?
| |
White |
Yellow |
Total |
| Before |
3 u |
1 u - 13 |
4 u - 13 |
| Change |
- 2 u |
+ 13 |
|
| After |
1 u |
1 u |
|
Comparing the white
and yellow files in the end |
1 |
1 |
|
Total number of files at first
= 3 u + 1 u - 13
= 4 u - 13
4 u - 13 = 191
4 u = 191 + 13
4 u = 204
1 u = 204 ÷ 4 = 51
Number of files that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 51
= 102
Answer(s): 102
