The length of a telephone call made to a company is denoted by the continuous random variable T. It is modelled by the probability density function:
a) (5 points) Find out k.
f(t) = {kt (kt, 0≤ t ≤ 10 else
b) (5 points) Find out the probability that a phone call to the company is longer than 6.
c) (5 points) Calculate E(T) and V(T).