answer all questions with explanation

2. Suppose the wealth of a company at time n is given by the unbiased random walk n Un = 1000 + Yi, i- 1 where {Yi} are i.i.d. random variables, each taking the value of 1 or -1 with equal probability. The company wants to know the probability of reaching a wealth of 10000 before going bankrupt. (a) Define T = min {n : Un =0 or Un = 10000}. Express the event {T > n} in terms of U1, U2,... and hence determine whether T is a stopping time. (b) Assume that P(T