If B is a non-singular 4 × 4 matrix and A is its adjoint such that $|A| = 125$, then $|B|$ is
Answer & explanation
Correct answer: option 1
$A = adj\, B$
We know that $|A| = |adj\, B| = 125$
so $B\, adj\, B = |B|I_{4 × 4}$
applying mod
we get $|B||adj\, B|=|B|^4$
so $125 = |B|^3$
so $|B|=5$