SOLUTION: an unbiased coin is tossed three times in succession . what is the probability of obtaining 'tail' at least once

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Question 728909: an unbiased coin is tossed three times in succession . what is the probability of obtaining 'tail' at least once
Answer by jim_thompson5910(35256) About Me  (Show Source):
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P(3 heads) = (1/2)^3 = 1/8

P(At least one tail) = 1 - P(3 heads)

P(At least one tail) = 1 - 1/8

P(At least one tail) = 7/8