A boat on the Tennessee River travelleed 30 miles downstream (with the current) in 2 hours. The return trip against the current took 6 hours. What are the speeds of the boat and the current?

Answer 1

boat speed: 10 mph, current speed 5 mph

distance = speed times time

30 miles = 15 mph x 2 hours downstream

30 miles = 5mph x 6 hours upstream

(b-c)6 = 30

(b+c)2 = 30

6b-6c = 30

2b+2c = 30

6b+6c =90

6b -6c = 30

subtract to get

12c = 60

c = 60/12 = 5 mph

2b = 30-2c = 30-10 = 20

b = 20/2 = 10 mph