
Step-by-step explanation
in the column we have
-have cell phones
-do not have cell phones
-total
and
in the other side.
-have a part time job
-do not have part time job,
so to know the number of students whoh fit both conditions ( have a cell phone and have a part time job) we need to find the cell where both intersect each other
hence, the answer is

I hope this helps you