JEE Main 2023MathematicsMatricesMediumMCQ

JEE Main 2023 — Matrices Question with Solution

JEE Main 2023 (24 Jan Shift 2)

Question

Let A be a 3×3 matrix such that adjadjadj.A=124. Then A-1adj A is equal to

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Show full solutionCorrect option: A
Correct answer
A23

Step-by-step explanation

Given equation is

adjadjadj.A=124

⇒A(n-1)3=124

∵ n=3

⇒A(3-1)3=124

⇒A8=124

⇒A2=12

⇒A=23

Now, A-1adj A=A-1.adj A=1A×A3-1

=A=23

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About this question

This is a previous-year question from JEE Main 2023, covering the Matrices chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.