If it's 45% for tails, 100 minus 45 is 55 for heads. For the fair coin, I have a 50% chance of tails and a 50% chance of heads. Fair enough. Now, I want to know, in either of these scenarios, what is the percent probability of getting four heads? So if given I've got the unfair coin, the probability of getting four heads is going to be 55% for each of those flips. So the probability of getting exactly four heads is going to be 0.55 times 0.55 times 0.55 times 0.55. And so the probability of picking an unfair coin and getting four heads in a row is going to be equal to 3 4ths times all of this business over here.