Selena drove at an average speed of 50.55 miles per hours for 1.75 hours. she stopped at a rest stop and then drove at an average speed of 45.2 miles per hour for 2.25 hours. did selena drive more miles before or after the rest stop? how many more miles?

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.