NDA 2025 · PYQ · Probability / Binomial distribution · medium
Let X be a random variable following binomial distribution with parameters n = 6 and p = k. Further, 9P(X = 4) = P(X = 2). What is the value of P(X = 3)?
A.135/1024✓ Correct
B.5/128
C.45/1024
D.70/1024
Explanation
With k = 1/4 and n = 6, P(X = 3) = C(6,3)·(1/4)³·(3/4)³ = 20·(1/64)·(27/64) = 20·27/4096 = 540/4096 = 135/1024.
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