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A coin is tossed three times. Let X denote the number of times a tail follows a head. If and ^2 denote the mean and variance of X , then the value of 64 ( + ^2 ) is :

Options

  1. A51
  2. B64
  3. C32
  4. D48

Correct answer

D. 48

Step-by-step solution

aligned & = x_i P_i= 1 2 & ^2= x_i^2 P_i- ^2 & = 1 2 - 1 4 = 1 4 & 64 ( + ^2 )=64 [ 1 2 + 1 4 ] & =64 3 4 =48 aligned

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