A boat travels in a straight path down the Nile river and then travels in a straight path back to the point it started. If no current existed, then the entire trip would take 1 hour. If there is a constant downstream current for the duration of the trip, how long will the entire trip take?
Hint: You can solve this problem very quickly using limits to think about it! (Or check out the solution if you want to see how this technique works.)