Question

If a matrix $A$ is of order $3\times 4$ and a matrix $B$ is of order $4\times 3$, then the order of $BA$ is

• A. $3\times 3$
• B. $4\times 4$
• C. $4\times 3$
• D. Not defined

Answer 1

Answer: (B)

$4\times 4$

$\text{If matrix A of order}m\times n\text{and matrix B is of order}n\times p,\text{then order of AB is}m\times p.$
$\text{Here, matrix A of order}3\times 4\text{and matrix B is of order}4\times 3.$
$\therefore \text{Order of BA is}4\times 4.$
Option B is correct.