3
$\begingroup$

I'm having trouble with an exercise in "Introduce to the theory of group" book. This is problem:

Let $M$ be a maximal subgroup of $G$. Prove that if $M$ is a normal subgroup of $G$, then $[G: M]$ is finite and equal to a prime.

  • 2
    Hint: there's one main thing we do with normal subgroups, which is to quotient by them.2012-10-14

2 Answers 2