Plz help me. Does anybody know the answer ?

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

The graph below shows the height of a projectile t seconds after it is launched. if acceleration due to gravity is -16 ft/s2, which equation models the height of the projectile correctly?

The anwser cause i do not understand just plez