Please help this is so difficult

Me what is the value of x? showing work would be appreciated - ! : )

Four airplanes carrying a total of 400 passengersarrive at the detroit airport. the airplanes carry, respectively,50, 80, 110, and 160 passengers.a) one of the 400 passengers is selected uniformly at random.let x denote the number of passengers that were on theairplane carrying the randomly selected passenger. find var(x)for x as given in the problemb) one of the 4 airplane drivers is also selected uniformly atrandom. let y denote the number of passengers on the chosen driver’s airplane. find var(y) for y as given in the problem

Determine the intercepts of the line that passes through the following points. (15,-3)(15,−3) (20,-5)(20,−5) (25,-7)(25,−7)