How would i solve this? calculus

Add or subtract polynomial : –12qr? +13rq?

The diameter of a ball is 8 in. what is the volume of the ball? use 3.14 for pi. enter your answer as a decimal in the box. round only your final answer to the nearest hundredth.

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