The amount of money in a bank account increased by 21.5% over the last year. If the amount of money at the beginning of the year is represented by n, which expression represents the amount of money in the bank account after the increase? A: n + 0.215n
B: n + 21.5n
C: 0.215n
D: 21.5n

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.