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A coin is biased so that heads comes up thrice as likely as tails. In four independent tossess of the coin, what is probability of getting exactly three heads?

Options

  1. A81 256
  2. B27 64
  3. C27 256
  4. D9 256

Correct answer

B. 27 64

Step-by-step solution

Heads comes up thrice as likely as tails P(H)=3 P(T) and P(H)+P(T)=1 P(H)= 3 4 P(T)= 1 4 P(3 head and 1 tail )= 3 4 3 4 3 4 1 4 = 27 256

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