Question

A boat covers a certain distance downstream in 3 hours, and it covers the same distance upstream in 5 hours. If the speed of the boat in still water in 8 km / hr, hen the speed of the stream is


1.1 km/hr
2.1.5 km/hr
3.2 km/hr
4.3 km/hr

Answer 1

Answer:

none of this

Step-by-step explanation:

Speed of boat in still water be u km/hr.  

Then, distance covered downstream =(u+1)×8=8u+8

Distance covered upstream =(u−1)×10=10u−10

Since the distance both ways is the same,  

8u+8=10u−10

⇒2u=18

⇒u=9 km/hr

∴ Distance covered one way =(9+1)×8 km

=80 km