The current on a portion of the Mississippi River is 3 miles per hour. A barge can go 6 miles upstream in the same amount of time it takes to go 10 miles downst

Question

The current on a portion of the Mississippi River is 3 miles per hour. A barge can go 6 miles upstream in the same amount of time it takes to go 10 miles downstream. Find the speed of the boat in still water.

 

 

Answer 1

Hi Travis, Let the speed of boat in still water be 'x' miles per hr

 

the speed of boat while going upstream = Su = x-3

the speed of boat while going downstream = Sd = x+3

 

Given that the time taken is same i.e.

 

6/x-3 = 10/x+3

 

6(x+3) = 10(x-3)

 

6x + 18 = 10x - 30

 

18 + 30 = 10x - 6x

 

48 = 4x 

x = 12

 

the speed of the boat in still water is 12 miles per hour