Help me plz :(((

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

What is the missing step in this proof ?

Human body temperatures have a mean of 98.20° f and a standard deviation of 0.62°. sally's temperature can be described by z = 1.4. what is her temperature? round your answer to the nearest hundredth. 99.07°f 97.33°f 99.60°f 100.45°f