If a fair coin will be flipped three times, what is the probability of flipping at least two heads in a row? Express your answer as a common fraction.
List all the possibilities:
H H H *
H H T *
H T H
H T T
T H H *
T H T
T T H
T T T
3 out of the 8 possibilities will have at least 2 heads in a row.
So, the probability is 3/8.