Adime is flipped 3 times. what is the probability that tails occurred all 3 times?

For three tosses of the coin all the possible outcomes are:
.
H-H-H
T-H-H
H-T-H
H-H-T
T-H-T
T-T-H
H-T-T
T-T-T

These eight possible outcomes are the sample space.
To find the probability of tossing tails tree times look down the sample space list and find any outcome that has exactly two H's.
The possibilities are only T-T-T.
This means that one of the eight possible outcomes contain exactly three tails. Therefore,
the probability of throwing exactly two heads in three tosses of the coin is 1 out of 8,