A student earned grades of 78, 72, 74, and 88 on her four regular tests. She earned a grade of 79 on the final exam and 88 on her class projects. Her combined homework grade was 89. The four regular tests count for 40% of the final grade, the final exam counts for 20%, the project counts for 10%, and homework counts for 30% What is her weighted mean grade? Round to one decimal place.
O A. 82.5
OB. 71.0
O C. 63.6
OD. 81.5

Someone . me. compound probability

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

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