Om has $10 that he wants to use to buy pens and pencils. however, he does not want to buy more pens than pencils. a pen costs $3, and a pencil costs $1. which graph represents this scenario? (here, x represents the number of pens and y the number of pencils.)

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.