SOLUTION: Four fair coins are flipped. What is the probability of getting three or more heads?

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Question 610796: Four fair coins are flipped. What is the probability of getting three or more heads?
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
We could use a binomcdf but this is very easy to do by hand.

P(4 heads) is simply (1/2)^4 = 1/16.

P(3 heads) is (4C3)(1/2)^4 = 1/4.

Therefore P(3 or more heads) is equal to 1/4 + 1/16, or 5/16.