Posted by ruca on .
A man who can row in still water at 3 mph heads directly across a river flowing at 7 mph.
At what angle to the line on which he is heading does he drift downstream and at what speed does he drift downstream?

precalculus 
drwls,
He drifts downstream at the river's speed, 7 mph. He has a 3 mph component across the river.
His direction with respect to the heading angle (straight across) is
tan^1 7/3 = 66.8 degrees (towards downstream)