The total use of electricity in the United States was 0.4 trillion kilowatt-hours in 1950 and about 2.8 trillion kilowatt-hours in 1990. How many times more electricity was there in 1999 than 1950? Use scientific notation

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 slope of the line that contains the points (-2,1) and (0,-3)

How can constraints be used to model a real-world situation?