The ratio between the time taken by a boat to cover a certain distance in upstream and the same distance in downstream is 5:1 respectively. The same boat can cover the same distance which was covered in upstream in still water in (35/3) hours. If the speed of the stream is 60 km/h, then find out the distance covered by the boat in downstream.

Solution

Let’s assume the speed of boat in still water and the speed of stream are ‘B’ and ‘C’ respectively. The ratio between the time taken by a boat to cover a certain distance in upstream and the same distance in downstream is 5:1 respectively. Let’s assume the distance covered in each stream by the boat is ‘d’ km. [d/(B-C)] / [d/(B+C)] = 5/1 (B+C)/(B-C) = 5/1 (B+C) = 5(B-C) B+C = 5B-5C 5B-B = 5C+C 4B = 6C 2B = 3C If the speed of the stream is 60 km/h. 2B = 3x60 = 180 B = 90 The same boat can cover the same distance which was covered in upstream in still water in (35/3) hours. d/90 = 35/3 d/30 = 35 d = 35x30 d = 1050 km The distance covered by the boat in downstream = 1050 km