1. The approximate total surface area of Earth is 5.1 x 10^8 k^2. All the salt water on Earth has an approximate surface area of 352,000,000 km^2, and all the
freshwater on Earth has an approximate surface area of 9x10^6 km^2. How
much of Earth's surface is covered by water, including both salt and fresh water?
Write your answer in scientific notation.*

2. How much of Earth's surface is covered by land? Write your answer in
scientific notation.
Your answer

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