Mrs. Summers polled the students in her 7th and 8th grade classes to determine the number of pets each student has at home. The results for her 7th grade class are shown in the dot plot below.

How many students are in Mrs. Summers' 7th grade class?
What percentage of the students have at least one pet at home? Round to the nearest percent.
Calculate the mean (rounded to the nearest tenth), median, and mode of the data represented on this dot plot.

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