Kathy had some money. she spent half the money on groceries. she spent 1/4 of the money on gas. she had $5.00 left. how mucb did she start with?

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.