Answer
B is the inverse of A
Work Step by Step
When there is an inverse of a matrix $A A^{-1}$ = I (the Identity Matrix)
AB = $\begin{bmatrix}
3(.4) + 2(-.1) & 3(-.2) + 2(.3) \\
1(.4) +4(-.1) & (1)(-.2) + 4(.3)\\
\end{bmatrix}$ = $\begin{bmatrix}
1 & 0\\
0 & 1
\end{bmatrix}$
Since AB equals the identity matrix, B is the inverse of A.
