There are 50 students going on the band field trip. They are planning on using two methods of traveling. They will use cars that can hold 5 students each and vans that can hold 7 students each. Let x represent the number of cars used and let y represent the number of vans used . Which of the following equations would be used to represent the situation? A. x + y = 50
B. 5y = 7x + 50
C. 5x - 7y = 50
D. 5x + 7y = 50

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.