Medium MCQ +4 / -1 PYQ · JEE Mains 2025

Let $\mathrm{A}=\left[\mathrm{a}_{\mathrm{ij}}\right]$ be a square matrix of order 2 with entries either 0 or 1 . Let E be the event that A is an invertible matrix. Then the probability $\mathrm{P}(\mathrm{E})$ is :

  1. A $\frac{3}{8}$ Correct answer
  2. B $\frac{1}{8}$
  3. C $\frac{3}{16}$
  4. D $\frac{5}{8}$

Solution

<p>C-I $\left|\begin{array}{ll}1 & 1 \\ 0 & 1\end{array}\right| \rightarrow 4$ ways</p> <p>C-II $\left|\begin{array}{ll}1 & 0 \\ 0 & 1\end{array}\right| \&\left|\begin{array}{ll}0 & 1 \\ 1 & 0\end{array}\right| \rightarrow 2$ ways</p> <p>$\mathrm{P}=\frac{\text { favourable }}{\text { total }}=\frac{6}{16}=\frac{3}{8}$</p>

About this question

Subject: Mathematics · Chapter: Probability · Topic: Classical and Axiomatic Probability

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