Marco is reconstructing his expenses for the past two weeks. Here are the records of his expenses: Transaction
Cost ($)
T-shirt
20
Gas
22
Movie
13
Video game
39
Jeans
34
Hat
15
Books
31

Marco’s bank statement says that he has an ending balance of $81. What is Marco’s starting balance?

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