Please help! I need the answer for b !!

Twenty-five percent of the customers entering a grocery store between 5 p. m. and 7 p. m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

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

A. 90 degrees b. 45 degrees c. 30 degrees d. 120 degrees