The 480 students in a group are to be seated in rows so that there is an equal number of students in each row. Each of the following could be the number of rows EXCEPT  Select.
A) 4
B) 20
C) 30
D) 40
E) 90
Obviously the number of rows must be a factor of 480. The only option which is not a factor of 480 is E (90).   Answer: 90.
<result>E</result>
The 480 students in a group are to be seated in rows so that there is an equal number of students in each row. Each of the following could be the number of rows EXCEPT