Find the solution of given problem:
Problem: You are a member of a production crew filming a nature explorer in the Rocky Mountains. The explorer needs to swim across a river to his campsite. By watching debris flowing down the river, you estimate that the stream is flowing at 1.29 mph. In still water, he can swim at 1.54 mph.
Part A: At what angle with respect to the shoreline would you advise him to swim to travel directly across the stream to his campfire?
I need proficient help in the above problem. Thanks in advance.