Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar. Write the expression in simplest form.
(4+ + 3) – 21-45 - 1) =

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.