Does anyone know these??

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

Marie is creating a cross stitch pattern with rectangles all the same size. what is the perimeter of each rectangle with sides of lengths 3/4 inch and 2/3 inch

Marshall went to the state fair and bought 3 tickets. each ticket to the fair cost x dollars. after he bought the tickets, he had $3.25 left in change. write an expression that represents the amount of money, in dollars, that marshall had before he bought the tickets. n