A fair coin is tossed 100 times. The probability of getting tails an odd number of times is a. `1//2` b. `1//8` c. `3//8` d. none of these

Explanation

Let n be the total number of tosses.


Let X be the number of times head occurs


`P (7) = P(9)`


`Rightarrow \ ^n C_7 (1/2)^7 (1/2)^(n-7) = \ ^n C_9 (1/2)^9 (1/2)^(n-9)`


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