A class has between 20 and 30 students. Is there a group size which will fit every student into a group?

Question

Groups of 2,3or 4 don't work. Must be a whole number

Answer 1

The possible number of students is 21, 22, 23, 24, 25, 26, 27, 29

A grouping that would accommodate all, must be a common factor of all.

29 is prime.

No grouping possible.