Simple Probability Coin Flipping

A fair coin is flipped four times. What is the probability of getting tails exactly twice? Write your answer as a simplified fraction.

I don't understand this question, could someone please explain how to get the answer.

50% or 0.5

Each flip has two outcomes: heads or tails. Each outcome has an equal probability of occurring. Therefore if you flip four times, it is most likely that you will see each outcome twice or two heads and two tails.

Dude... thanks for picking my answer as best but its wrong. Paula's was much better.

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On every flip there are one of two possibilities: head (H) or tails (T). So overall there are 16 possibilities:
HHHH
HHHT (i.e. heads, then heads, then heads, then tails)
HHTH
HHTT *
HTHH
HTHT *
HTTH *
HTTT
THHH
THHT *
THTH *
THTT
TTHH *
TTHT
TTTH
TTTT

The ones with a * next to them have exactly two tails. So since that's 6 of the 16 equally likely possibilities, the probability is 6/16, which cancels down to 3/8

Total possible outcomes = 2^4 = 16
Successful outcomes
TTHH
THHT
HTTH
HHTT
THTH
HTHT
=6
P = 6/16 = 3/8

50% / 50%

C(4,2) (0.5^4) = ...calculator