Tossing a coin. X is the number tosses. What is the probability that X is an odd number?

A "fair" coin is tossed until the first time we get tails. Let X be the number tosses. What is the probability that X is an odd number?

A "fair" coin is tossed until the first time we get tails. Let X be the number tosses. What is the probability that X is an odd number?