Ricardo has a $50 gift card for an electronic store. he also has a coupon good for $10 off his purchase. Let a represent the amount of merchandise Ricardo can buy from the store using his gift card and coupon. Write and solve any quality to represent the situation. Graph the solution set on the number line

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.