An observer standing on the southern bank of a river sees a tree that is much more than 100 feet downstream on the northern bank of the river. The angle formed by the southern bank and the line from the observer to the tree is 15 ∘. After walking 100 feet downstream, the observer measures the angle formed by the southern bank and the line to the same tree to be 25 ∘. Find the width of the river. (can you show the work please)(also the drawing please)

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.