Your question is Correlation From Coin Tosses. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
A coin is tossed three times. Define X = 1 if toss 1 is T and toss 3 is H, otherwise X = 0. Define Y = 1 if toss 2 is H and toss 3 is H. Calculate the correlation.