An unbiased coin is tossed four times. The coin lands heads exactly once

Question

An unbiased coin is tossed four times. Find the probability of the given event. (Enter your answer to five decimal places.)

The coin lands heads exactly once

Answer 1

probability = # ways what you want happens / # ways everything happens

# of ways you can get heads exactly once- "4 choose 1" or 4! / (3!*1!) = 4

# of ways you can flip a coin 4 times = 2^4

4 / 2^4

4 / 16

1/4

P(exactly 1 heads when flipping a fair coin 4 times) = 1/4