You flip three coins. what isthe probability that you get at least two heads, given that you get at least one head?

1/2
If there is one head and one tail for each coin the probability would be 1/2. There are two terms with only one answer 1/2.

OR

If you are asking for the end result of heads and the coins you would get 2/3. There are three terms with only one answer. 2/3.