In a college, 200 students are randomly selected. 140 like tea, 120 like coffee and 80 like both tea and coffee. Number of students who like at least one of tea or coffee is 

60

200

100

180

Use the elimination method to solve the systems of equations. choose the correct ordered pair. 7x+4y=39

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.

Can someone explain to me how to do