A fair coin is flipped 4 times. What's the probability of tails appearing on at most one of the four flips?

Question

A fair coin is flipped 4 times. What's the probability of tails appearing on at most one of the four flips?

The answer I get is 4/16, but the answer cheat says 5/16.

Answer 1

You need to find the probability tails appears either zero times or once.

The probability it appears zero times is $\dfrac{1}{16}$.

I think you have worked out the probability it appears exactly once.

Answer 2

You have to add in the possibility that no tails appear.