Q.

A coin is biased so that a head is twice as likely to occur as a tail. If the coin is tossed 3 times, then the probability of getting two tails and one head is               [2024]

1 227  
2 29  
3 127  
4 19  

Ans.

(2)

Let x be the probability of getting a tail.

 P(T)=x;  P(H)=2x

 x+2x=1x=13

 P(T)=13 and P(H)=23

Now, required probability=C23×13×13×23

=3×227=29