CBSE Class 12 Sample Paper for 2026 Boards

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Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Question 5 - CBSE Class 12 Sample Paper for 2026 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at August 26, 2025 by

[MCQ] The inverse of the matrix is…- CBSE Sample Paper Class 12 - CBSE Class 12 Sample Paper for 2026 Boards

part 2 - Question 5 - CBSE Class 12 Sample Paper for 2026 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12
part 3 - Question 5 - CBSE Class 12 Sample Paper for 2026 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12
part 4 - Question 5 - CBSE Class 12 Sample Paper for 2026 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12

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Question 5 The inverse of the matrix [■(3&0&0@0&2&0@0&0&5)] is... (A) [■(0&0&3@0&2&0@5&0&0)] (B) [■(1/3&0&0@0&1/2&0@0&0&1/5)] (C) [■(−1/3&0&0@0&−1/2&0@0&0&−1/5)] (D) [■(−3&0&0@0&−2&0@0&0&−5)]Let given matrix be A = [■(3&0&0@0&2&0@0&0&5)] Since all elements are zero except diagonal elements This is a diagonal matrix And, inverse of diagonal matrix is reciprocal of each element on the diagonal Since (b) matches this, let’s test it out Checking Option (b) Let A–1 = [■(1/3&0&0@0&1/2&0@0&0&1/5)] Now, this should be true AA–1 = I Finding AA–1 Putting values [■(3&0&0@0&2&0@0&0&5)] [■(1/3&0&0@0&1/2&0@0&0&1/5)] =[■(3(1/3)+0+0&3(0)+0(1/2)+0&3(0)+0+0(1/5)@0(1/3)+2(0)+0&0+2(1/2)+0&0+2(0)+0(1/5)@0(1/3)+0+5(0)&0+0(1/2)+5(0)&0+0+5(1/5) )] = [■(𝟏&𝟎&𝟎@𝟎&𝟏&𝟎@𝟎&𝟎&𝟏)] = I Thus, for option (b) AA–1 = I So, the correct answer is (B)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 15 years. He provides courses for Maths, Science and Computer Science at Teachoo