Question

If $\left[A\right]$ is a matrix of $3\times 3$ order and $|A|=5$, then $|adjA|=$ what?

• A. $250$
• B. $125$
• C. $625$
• D. $25$

Answer 1

The correct option is D $25$

For a square matrix of order $n$,

$|adjA|=|A{|}^{n-1}$

Here,

$|A|=5$

So,

$|adjA|=5^{(3–1)}=25$