?Ł ₩øʉⱡđ ɽɇ₳ⱡⱡɏ ⱡł₭ɇ ɏɇ₴₮ɇɽđ₳ɏ, ₴ⱨɇ ₲łvɇ ₥ɇ ₮ⱨɇ ₳₦₴₩ɇɽ, ₳₦đ ₦ø₮ jʉ₴₮ ₣øɽ đɽ₳₥₳, Ł đø₦'₮ ₭₦ø₩ ₩ⱨ₳₮ øʉɽ ₦ʉ₥฿ɇɽ₴ ₳ɽɇ ₦ø₮ ₣₳₵₮øɽ₴ 5, ฿ʉ₮ Ł ₩øʉⱡđ ⱡł₭ɇ ɏøʉ ₮ø ₮ɇⱡⱡ ₥ɇ ɏøʉ ₳₦₴₩ɇɽ ₩ⱨ₳₮ ₮ⱨø₴ɇ 2 ₦ʉ₥฿ɇɽ₴ ₳ɽɇ

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.