(a) Show that P(S(t)

(a) Show that P (S (t) < K) N (t)). (In Tl calculators, you can use normalcdf(lower, upper, expectation, standard deviation) to calculate the cumulative probabilities for normal random variables.) (b) Suppose that a non-dividend-paying stock with a current price of $75 has an instantaneous annual expected return of 12% and annual volatility of 10%. What is the probability that 3 months from now, the stock's price is less than its current price? i.e. P (S (0.25) < 75).