1.

If A is a square matrix of order 5 and det A = 1/9, then what is det |(3A)-1| equal to?  1. 1/812. 1/273. 1/94. 1/125

Answer» Correct Answer - Option 2 : 1/27

Concept:

Let A is a square matrix having order n.
det A-1 = 1/(det A)
 

Calculation:

Here, det A = 1/9

det |(3A)-1| = (3-1)5 det (A-1) .....(∵ Order = 5)

\(\frac {1}{3^5}\)× 1/detA

\(\frac {1}{3^5}\)× 9

= 1/33

= 1/27

Hence, option (2) is correct.



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