If a fair coin is flipped four times in a row, what is the probability that there will be at least one head and one tail? Choose the correct choice
A) 3/4	B) 7/8	C) 15/16	D) 31/32	E) 63/64
The number of possible outcomes is 2^4 = 16   There is one way to get no heads and one way to get no tails.   Thus there are 14 outcomes with at least one head and one tail.   P(at least one head and one tail) = 14/16 = 7/8   The answer is 7/8.
<result>B</result>
If a fair coin is flipped four times in a row, what is the probability that there will be at least one head and one tail?