Question 1025688
The distance between two piers on a river is 43.2 miles. It takes a motorboat, moving downriver, 2 hr 24 min to complete the journey. How much time does it take the same boat to go back upstream if the current flows at 1.8 mph?
2 hr 24 min=2.4 hrs
let x=speed of motorboat in still water

 speed=distance/travel time=43.2/2.4=18 mi/hr(speed downstream)
x+1.8=18
x=16.2 mph(speed of motorboat in still water)
16.2-1.8=14.4 mph(speed upstream)
43.2/14.4=9 hrs
 How much time does it take the same boat to go back upstream? 9 hrs