Hi Mauli.. :)
Q31) P(A winning) = B wins the first match and then A wins in the subsequent matches
+ A wins in the first match and then A wins in the subsequent matches.
= [BCAA+BCABCAA+BCABCABCAA+....]
+[AA+ACBAA+ACBACBAA+.........]
= [(1/2)2 + (1/2)5 + (1/2)8 + (1/2)11 +…]
+[(1/2)4+ (1/2)7 + (1/2)10 + ……]
= 4/14 + 1/14
= 5/14
Q32) As A and B are symmetric players . Probability of winning must be the same.
P( B winning) = 5/14.
Therefore, P(C winning) = 1- P(A winning) - P(B winning)
= 1-5/14-5/14
= 2/7
Q33) If the game continues indefinitely ie.
like ACBACBACB....
then, its same as finding limit (as n tends to infinity) (1/2)^n, which is equal to zero.
:)