Let X be the number of flips we make before seeing heads. We need to count how many have the same number of heads in the first and second half. There are 100 total flips, so [math]2^{100}[/math] possible sequences of flips. $\begingroup$ Let P equal probability that A wins. See more ideas about Gymnastics poses, Poses, Best friend pictures. Two people have been hospitalised following a serious crash that closed the M20 in both directions. Let p be the probability of getting tails on any one flip. And note three things that, individually, aren't too hard to see: Coin flipping is a memoryless process. Can you convince yourself that P = probability A wins on first toss + probability that A wins on third or later = 1/2 + (Probability neither A nor B wins in the first two tosses)P = 1/2 + (1/4)P. Apr 27, 2014 - Explore kelly7042's board "2 person gymnastics Poses", followed by 233 people on Pinterest. We must flip the coin at least once in order to get heads (or tails, or anything).