Katie bought 4 sweaters that each cost the same amount and 1 skirt that cost $20.the items she bought cost a total of 160$ before tax was added. what was the cost of each sweater

An equation where variables are used to represent known values—function notation true or false

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?

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.