Use guess and check to find when an exponential function with a decay rate of 15% per hour reaches half of its original amount, rounded up to the nearest hour. the exponential function reaches half of itsoriginal amount after how many hours?

Your friend swims on the school team. in his first four races, his times are 24.7, 23.5, 25.6, and 27.2 seconds. which time listed for his next race would make the range larger?

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

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?