CUET · MATHS · PYQ PAPER 2025
The random variable X has a probability distribution \(P(X=r)=\left\{\begin{array}{ll}r k, & \text { if } r \leq 2, \\ (r-1) k, & \text { if } 2 < r \leq 4, \text { where } r \in N \cup\{0\} \text { and } k \in R . \\ 0, & \text { otherwise },\end{array}\right.\), where \(n\) is the set of natural numbers
(A) \(k=\frac{1}{9}\)
(B) \(P(2 \leq X \leq 3)=\frac{1}{2}\)
(C) \(P(X=4)=\frac{1}{3}\)
(D) \(P(X>1)=\frac{7}{8}\)
Choose the correct answer from the options given below:
- A (A) and (C) only
- B (A), (C) and (D) only
- C (B) and (D) only
- D (A) and (D) only
Answer & Solution
Correct Answer
(C) (B) and (D) only
Step-by-step Solution
Detailed explanation
\(\sum P(X=r) = P(X=0)+P(X=1)+P(X=2)+P(X=3)+P(X=4) = 1\) \(0k + 1k + 2k + (3-1)k + (4-1)k = 1\) \(8k = 1 \implies k = \frac{1}{8}\) \(P(2 \leq X \leq 3) = P(X=2)+P(X=3)\) \(P(2 \leq X \leq 3) = 2k + 2k = 4k\) \(P(2 \leq X \leq 3) = 4(\frac{1}{8}) = \frac{1}{2}\)…
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