A coin is biased so that the head is 3 times as likely to occur as tail. If the coin is tossed twice, find the probability distribution of number of tails.

Explanation

If `P(H)` and `P(T)` are probablity of occurance of head and tail respectively, then,

We are given,

`P(H) = 3P(T)`

Also,`P(H)+P(T) = 1`

`4P(T) = 1=>P(T) = 1/4`

`P(H) = 3P(T) = 3/4`

If coin is tossed twice and both outcomes are head,`P(X=0) = 3/4**3/4 = 9/16`

If coin is tossed twice and first outcome is tail and second is head`= 1/4**3/4 = 3/16`

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