A boat traveled downstream a distance of 152 mi and then came right back. If the speed of the current was 7 mph and the total trip took 6 hours and 20 minutes, find the average speed of the boat relative to the water.

Question

perl · Answer

|dw:1413512916867:dw|

perl · Answer

A boat traveled downstream a distance of 152 miles and then came right back.
If the speed of the current was 7 mph and the total trip took 6 hours and
20 min, find the average speed of the boat relative to the water
:
Let s = average boat speed in still water
then
(s+8) = speed (relative to land) downstream
and
(s-8) = speed (relative to land) upstream
:
Change 6 hr 20 min to 61%2F3 hr

perl · Answer

Change 6 hr 20 min to 6 and 1/3 hr