Need HELP!!!!

Mary lives in causeway bay and works inwanchai.From Monday to Friday morning, she can go to the workplace by tram, on foot or by MTR. In each morning, she has a probability of 0.5 by tram, 0.3 on foot and 0.2 by MTR. The tram fee is $2 and MTR fee is $3.2.Let X be the traveling fee she will spend in a morning. In this question, the traveling fee in the evening is not considered.

a. What are the expected value and variance of the traveling fee in a morning?

b. What are the expected value and variance of the traveling fee in a week?

c.What is the expected number of days that she will go to workplace not on foot in a week?

d.Suppose Mary went to the workplace on foot on Monday and Tuesday. What is the expected traveling fee for the rest of the week?