In the cube $ABCDA'B'C'D'$, we have $3\overrightarrow{AM}=\overrightarrow{MD}$ and $2\overrightarrow{D'N}=\overrightarrow{NB'}$.
Find the points $M$ and $N$ in the cube;
So, i can't find a way to discover these points. Every method I've tried ended up with something illogical.