Stuck on this question.
The experiment of tossing a fair coin until three consecutive heads appear is performed. Let X be the number of tosses, and Y be the number of tails that appear. Find the probability p(Y = 1).
I tried listing out the possibilities where Y=1:
THHH HTHHH HHTHHH
So I thought maybe it's 3/(2^6) but that's not listed as an answer.