1/3 of the students in Mr. Wilson's class play basketball and 1/2 play football. What combined fraction of students in Mr. Wilson's class plays either basketball or football?

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.