Is this in standard form ? if it isn't then what would it be in standard form ?

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

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)