Let $M$ and $N$ be normal subgroups of $G$ s.t. $G=MN$. Prove that $G/(M\cap N)\cong (G/M)\times (G/N)$.
I have got the proof. But the question asks to draw the lattice. Is there any lattice? Since we don't know what's the groups $M$, $N$ and $G$ are like.
What's the lattice?