Question

A boat whose speed is 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes.

Answer 1

Answer:

=> x = 5 km/hr

Step-by-step explanation:

Let's assume that the speed of stream is = x km/h

Speed of boat in still water v = 15 km/h

Total time taken = 4 hour and 30 mins or 9/5 hrs

Distance covered (one way) = 30 kms

Then,

Speed of boat downstream =( 15 + x ) km/h

Time taken downstream = (30/15 + x ) hrs

As time = distance / speed

Speed of boat upstream = ( 15 - x ) km/h

Time taken upstream =( 30/15 - x ) hrs

Now,

Total time taken = Time taken downstream + Time taken upstream

9/2 = (30/15 + x ) + (30/15 - x )

Skipping the calculation part ( I was gonna type it out but i realized it'll take a LOT of time + you guys are smart enough to do that)

x = 5 km/h

The speed of the stream is 5 km/h

Answer 2

Answer:

Hope this attachment helps you dear......