What is the average number of coin tosses required to flip both sides at least once?
On average, how many coin tosses in a row are required to flip both a heads and a tails at least once? For example the sequence HHTH required 3 flips, while the sequence THHT required 2 flips to get at least one tail and one head.
It is important to note that I said “on average.” If I left that out, the answer would be infinity. Since I did say “average”, you have to take into account the percentage of times that you expect each thing to happen.
This question is in the General Section. Responses must be helpful and on-topic.