Linear Systems & Matrices · Superchallenge problem

Solve the matrix equation $XA=B$ for $X$, where $A=\begin{bmatrix} 3 & 1 \\ 2 & 1 \end{bmatrix}$ and $B=\begin{bmatrix} 1 & 0 \\ 1 & 1 \end{bmatrix}$. (Note the side on which $A$ appears.)