3. In a race between Alpha and Beta, let Xt denote the amount of time (in seconds) by which Alpha is ahead when lOOt percent of the race has been completed. Assume that (X00351 can be modeled by a BM with drift 0 and variance parameter 02. If Alpha is leading by 0/2 seconds after three-fourths of the race is complete, what is the probability that she is the winner