What is the probability of tossing one coin for two 'tails' in a row?

Assuming the coin is fair, probability of getting one tail is 50%, probability of getting two tails in a row is 50%*50% = 25% or 1/4

The probability of tossing two tails in a row is 1/2 possibility tossing tails the first time, then another 1/2 possibility of tossing tails again, so from the start, we would multiply 1/2 and 1/2 to get a 1/4 possibility of tossing two tails in a row.

Hope this helps and have a nice day:)