Show work and explain : ) a boat travels 3 hours downstream at x miles per hour. on the return trip, the boat travels 3 miles per hour slower and takes 4 hours. what is the distance the boat travels each way?

Nielsen media research wants to estimate the mean amount of time (in minutes) that full- time college students spend watching television each weekday. find the sample size necessary to estimate the mean with a 15-minute margin of error. assume that a 95% confidence level is desired. also assume that the population standard deviation is known to be 112.2 minutes.