Does every group of order $42$ have a normal subgroup of order $3$

abstract-algebrafinite-groupsgroup-theorynormal-subgroupssylow-theory

Does every group of order $42$ have a normal subgroup of order $3$?

I have both Sylow Theorems I can use. They imply that there are either $7$ or $1$ Sylow $3$-subgroups and the $7$ case is what makes me doubt whether the statement is true or false.

Can anyone please help me either prove or disprove this statement?

Best Answer

Hint. Group of order 42 $$ \begin{pmatrix} \mathbb{Z}_7^* & \mathbb{Z}_7\\ 0 & 1 \end{pmatrix} $$ has no normal subgroup of order $3$.

Check.