You are standing at the edge of a slow-moving river which is one mile wide and wish to return to your campground on the opposite side of the river. you can swim at 2 mph and walk at 3 mph. you must first swim across the river to any point on the opposite bank. from there walk to the campground, which is one mile from the point directly across the river from where you start your swim. what route will take the least amount of time ?