What was James's rowing speed in still water?

Question

James could row at 3 times the speed of the water in the river. He could row 16 miles downstream in 2 hours less than it took him to row 14 miles upstream.

Answer 1

 

Let x = speed of current

 

Then 3x = rowing speed

 

Speed upstream (against current) = 3x-x = 2x

Speed downstream (with current) = 3x+x = 4x

 

Distance = (Rate)(Time), so Time = Distance/Rate

 

Time to row 14 miles upstream - 2 = Time to row 16 miles downstream

 

So, 14/(2x) - 2 = 16/(4x)

 

           7/x - 2 = 4/x

 

             7 - 2x = 4

 

                -2x = -3     x = 1.5 mph = speed of current

rowing speed = 3x = 4.5 mph