Question : South African cricket captain lost the loss of coin 13 times out of 14. The chance of this happening was
(A) \dfrac{7}{2^{13}}
(B) \dfrac{1}{2^{13}}
(C) \dfrac{13}{2^{14}}
(D) \dfrac{13}{2^{11}}
Answer : option (A)
Solution :
L and W can be filled in 14 places in 2^{14} ways
therefore, n\left( s\right) =2^{14}
now 13 L’s 1 W can be arranged at 4 places in 14 ways, hence n(A) = 14.
therefore, P\left( A\right) =\dfrac{n\left( A\right) }{n\left( S\right) }=\dfrac{14}{2^{14}}=\dfrac{7}{2^{13}}.