Debbie traveled by boat 5 miles upstream to fish in her favorite spot. Because of the 4-mph current, it took her 20 minutes longer to get there than to return. How fast will her boat go in still water?
Let the speed in still water be mph
When it travels upstream its speed= mph
Time taken to go upstream= h
Speed in downstream = mph
Time taken to go downstream or time taken to return back= h
And 20 min hrs
But according to question...
Solve it and you will get the answer