What is the probability of flipping heads three times in a row?

Answer 1

(1/2)^3 = 1/8

In general it is like this (p/n)^t. Where n is the number of equally possible outcomes (2 since you can get heads or tails), p is the number of desired outcomes (1 since you only are concerned with heads), and t is the number of trials (3 in this case).

One caveat to this is that it does not factor in initial conditions. Although very slight you have a better chance of getting heads when the coin is flipped from a position where heads is up. You have less chance of getting heads when the coin is flipped from the tails-up position. This effect is decreased the more the coin flips before landing.