Suppose you want to row your boat across a 3-mile-wide river. You can row at a speed of 2.5 mi/h. The current is flowing south at a rate of 1.4 mi/h. At what angle upstream should you aim your boat so that is ends up going straight across?

Answer 1

if x=0 means straight across, you need to go upstream at an angle x where

sin x = 1.4/2.5

note that the 3-mile width and southward flow of the water are irrelevant