The probability that Mary will eat cheese on any given day is .6 while the probability that Becca will eat cheese on any given day is .25.
If these events are independent, what is the probability that Mary or
Becca will eat cheese on a randomly selected day,

The coverage of a base station of a telecommunication company forms a disk with a radius of (kilometers). let be the distance of a cellphone from a base station. assume that the location of cellphones in use are randomly uniformly distributed within the disk. calculate the mean and variance for the random variable.