Let $G$ be a group of order $105 = 3 \times 5 \times 7$ with a normal Sylow $3$-subgroup, prove that $G$ is cyclic.
My attempt
I've been able to show that $G = NP$, where $N$ is the normal Sylow $3$-subgroup (which is of course cyclic) and $P$ is a cyclic group of order $35$. What's left to be shown is that $NP$ is cyclic. And I'm stuck.
Any help would be greatly appreciated. Thanks in advance!