An unbiased coin is tossed seven times in a row, what is the probability of getting at least one head if on the first toss came the tail?
Correct Answer : a ) \(63 \over 64\)Explanation :
If on the first toss, the tail came, then there will be only 6 tosses remaining.
As the coin is unbiased, so there is a fair chance of getting a head and tail.
So, the total possible outcomes will be = 26 = 64
Thus, the number of outcomes on which no head came will be = 1
As we know that
Probability of getting no head if on the first toss tail came =\(1 \over 64\)
Therefore, probability of getting at least one head if on the first toss tail came = (1 – Probability of getting no head if on the first toss tail came)
Hence, (A) is the correct answer.
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