Please assist me solve the below question.

(i) Show that in a one-step binomial tree model of the price of a non-dividend- paying share, the risk-neutral probability q of an up movement is given by: u-d where d, u, r and or are quantities you should define. [5] (ii) Explain briefly why it must be assumed that decu. [2] (iii) (a) Write down a formula for @, the expected one-step rate of return on the share based on the real-world probability p of an up-movement. (b) Show that the real-world variance, of, of the one-step rate of return on the share is p(1- p)(u - d)2. [4] (iv) Show that p > q if and only if I+ 0> e" and interpret this result. [4] [Total 15]