Here is the question

A filling station is supplied with gasoline once a week. If its weekly volume of sales in thousands of gallons is a random variable with probability density function f(x) = {C(1-xlz, 0 5 x 5 1 0, otherwise a) To make x} as a valid probability density function, what value c can be? b} Calculate the expected value of X. c) Find P(x = 0.5) d) Find P(0.2 05)