 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2015/paper-2/10/b/solution

The number of tails has a binomial distribution. The complement of at least two tails consists of zero tails or exactly one tail. Therefore

P (at least two tails) = 1 - \frac{( 0 10 ) + ( 1 10 )}{2 ^{10}} = 1 - \frac{11}{1024} .

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