Question 27580
just by thinking of all the possible outcomes, we could get...


TTT
-----------
TTH
THT
HTT
-----------
THH
HTH
HHT
-----------
HHH


Each roll has a probability of 1/2...3 in a row is (1/2)*(1/2)*(1/2) --> 1/8


So Each of the 8 possible outcomes above has probability of 1/8.


We want P(2 tails) = P(HTT) + P(THT) + P(TTH)
--> 1/8 + 1/8 + 1/8
-->3/8


jon.