Question:
If $A$ and $B$ are two matrices of order $3 \times m$ and $3 \times n$ respectively and $m=n$, then the order of $5 A-2 B$ is
(a) $m \times 3$
(b) $3 \times 3$
(c) $m \times n$
(d) $3 \times n$
Solution:
Since, the order of both $A$ and $B$ are same.
i.e., $3 \times m$ or $3 \times n$.
Therefore, the order of $5 A-2 B$ is also $3 \times m$ or $3 \times n$.
Hence, the correct option is (d).