Barry owns a house on a river. The river flows at 3 miles per hour. Barry decides to start rowing downstream, with the current, at noon. He wants to return to his house at 5 p.m. At what time should Barry turn around and row home if he normally rows 5 miles per hour in water that has no current?
5 mph + 3 mph =8 mph - his rowing speed downstream
5 mph - 3 mph =2 mph - his rowing speed upstream
D = Distance
D / 8 + D / 2 ==5 hours, solve for D
D = 8 miles - distance he rowed one way
8 / 8 = 1 hour it took him to row downstream - which was 1:00 pm
8 / 2 = 4 hours it took him to row upstream and arrive home at 5:00 pm
