Julie and Eric row their boat (at a constant speed) 63 miles downstream for 7 hours, helped by the current. Rowing at the same rate, the trip back against the current takes 9 hours. Find the rate of the current.

Question

lgbasallote · Answer

downstream = speed of boat + current
upstream = speed of boat - current

63m/7 hr = speed of boat + current
9 mph = speed of boat + current

63m/9 hr = speed of boat - curent
7 mph = speed of boat - current

9 mph = speed of boat + current
7mph = speed of boat - current

16 mph = 2 spd of boat

speed of boat = 8 mph

so speed of current is 1 mph