Q87 / 180 · KCET 2025 · Mathematics
If $A$ and $B$ are two matrices such that $A B$ is an identity matrix and the order of matrix $B$ is $3 \times 4$, then the order of matrix A is
- A$3 \times 4$
- B$3 \times 3$
- Correct answerC$4 \times 3$
- D$4 \times 4$
Solution
$\begin{aligned}
& \mathrm{AB}=\mathrm{I} \\
& \mathrm{~A}_{4 \times 3} \mathrm{~B}_{3 \times 4} \rightarrow \mathrm{I}_{4 \times 4}
\end{aligned}$
$\rightarrow$ The order of matrix A is $4 \times 3$
Hence, the correct answer is option: 'C'.