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99 Percentile Qs Bank for JEE MainMathematicsProbability

A random variable X takes the values 0,1 and 2. If P(X=1)=P(X=2) and P(X=0)=0.4 , then the mean of the random variable X is

Options

  1. A0.2
  2. B0.7
  3. C0.5
  4. D0.9

Correct answer

D. 0.9

Step-by-step solution

We have, P(X=1)=P(X=2) ^1 1 ! e^ = ^2 2 ! e^ =2 Also, P(X=0)+P(X=1)+P(X=2)=1 aligned & 0.4+P(X=1)+P(X=2)=1 & P(X=1)+P(X=2)=0.6= 6 10 = 3 5 aligned Also, P(X=1)+P(X=1)= 3 5 [from (i)] aligned & P(X=1)= 3 10 & P(X=1)=P(X=2)= 3 10 & Mean X₀ P(X=0)+X₁ P(X=1)+X₂ P(X=2) & =0+1 3 10 +2 3 10 = 9 10 =0.9 aligned

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