Let's say you flip 2 coins simultaneously. There are 3 possible outcomes: Both are heads, both are tails, or one is heads and the other is tails. Does this mean that the probability of getting one head and one tail is 1/3?

Answer 1

Not quite. There are 4 possible outcomes

Coin1 Coin2
H H
H T
T H
T T

Two of those result in a tail and a head. So, the probability is 2/4 = 1/2