JEE Main 2016MathematicsMatricesMediumMCQ

JEE Main 2016 — Matrices Question with Solution

JEE Main 2016 (03 Apr)

Question

If A=5a-b32 and A.adjA=A AT , then 5a+b is equal to 

Choose an option

Show full solutionCorrect option: D
Correct answer
D5

Step-by-step explanation

A=5a-b32 and AT=5a3-b2

AAT=25a2+b215a-2b15a-2b13

Now, A.adjA=AI2=10a+3b0010a+3b

Given AAT=A.adj A

15a-2b=0 ......(i)

10a+3b=13 .......(ii)

Solving we get

5a=2 and b= 3

∴ 5a+b=5

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Matrices chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2016, 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.