Problema Solution

The speedOf a boat in still water is 15km/hr.It goes 30 km upstream and downstream to the original point in 4hrs 30minutes.Find the speed of the stream.

Answer provided by our tutors

Let the speed of the stream be x km/hr.

Speed of the boat down stream = (15+x) km/hr   (1/2 mark)

And, speed of the boat upstream = (15-x) km/hr   (1/2 mark)

Time taken by the boat to go 15 km downstream = hrs.   (1/2 mark)

   Time taken by the boat to go 15 km upstream  =    (1/2 mark)

Since total time taken by the boat in downstream and upstream is 4 hours 30 minutes ie . .

   (1 mark)

    (1 mark)

   (1/2 mark)

But speed cannot be negative Hence, the speed of the stream = 5km/hr