Johnny raises pigs and turkeys. While the animals were walking into the barn at night he counted 26 heads and 72 legs. How many pigs does he own? ​

What is the lcm of 16 and 40 ? 24 and 40 ?

Precalculus question, image attached.

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.