Question: You have 100 coins. 99 are fair and 1 is double sided. You pick a random coin and flip it 10 times and get 10 heads in a row. What is the probability that you picked the double sided coin? Response / help needed: Probablity of picking a 1 sided coin = .01 Probability of heads 10 times in a row with an fair coin = .5^(10) Probability of heads 10 times in a row with an unfair coin (assuming the head is on both sides) = 1 So, i think, according to baye's, the equation should be .01*1/ (.01*1+ .5^10*.99) = .912 Is that correct? Also, what would you do if you do not assume heads is on both sides?