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CUET · MATHS · PYQ PAPER 2025

Let \(X\) denote the number of hours a student studies on a selected day. The probability distribution of \(X\) is given by (where \(k\) is some unknown constant)
\(P\left(X=x_i\right)=\left\{\begin{array}{ll}0.5, & \text { if } x_i=0 \\k x_i, & \text { if } x_i=1 \\k\left(4-x_i\right), & \text { if } x_i=2 \text { or } 3 \\0, & \text { otherwise }\end{array}\right.\)
Then the value of \(k\) is

  1. A \(k=\frac{1}{4}\)
  2. B \(k=\frac{1}{3}\)
  3. C \(k=\frac{1}{8}\)
  4. D \(k=\frac{1}{2}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(k=\frac{1}{8}\)

Step-by-step Solution

Detailed explanation

\(\sum P(X=x_i) = 1\) \(P(X=0) + P(X=1) + P(X=2) + P(X=3) = 1\) \(0.5 + k(1) + k(4-2) + k(4-3) = 1\) \(0.5 + k + 2k + k = 1\) \(0.5 + 4k = 1\) \(4k = 0.5\) \(k = \frac{0.5}{4}\) \(k = \frac{1}{8}\)