If A is a matrix of order $m×n$ and B is a matrix such that AB' such that B'A are defined, the order of matrix B is :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $m×n$
Let $B = B_{p×q}⇒B'=B'_{q×p}$
$A=A_{m×n}$
if $AB'$ is defined then $n=q$
So $B'A$ is defined then $p=m$
So order of B is $m×n$