Question

Find the probability of each event

A fair coin is flipped ten times. What is
the probability of the coin landing tails up
at least nine times?

Answer 1

11/1024.

Explanation:

Binomial Probability distribution.

This is the probability of 9 tails or 10 tails being flipped.

Prob ( 10 tails) = (1/2)^10 = 1/1024

Prob ( 9 tails) = 10C9 * 1/2^9* 1/2 = 5/512

Required probability = 1/1024 + 5/512

= 11/1024.