SSC Sample Paper Mock Test-14 SSC CGL Tear-II Paper-1

A steamer goes downstream from one port to another in 4 h. It covers the same distance upstream in 5 h. If the speed of the stream is 2 km/h, the distance between the two ports is

A) 50 km

B) 60 km

C) 70 km

D) 80 km

Correct Answer: D

Solution :

Let the distance between the two ports be x km.

Then, Speed downstream \[=\frac{x}{4}\text{km/h}\]

Speed upstream \[=\frac{x}{5}\text{km/h}\]

speed of the stream \[=\frac{1}{2}\left( \frac{x}{4}-\frac{x}{5} \right)\]

\[\therefore \] \[\frac{1}{2}\left( \frac{x}{4}-\frac{x}{5} \right)=2\]

\[\Rightarrow \] \[\frac{x}{4}-\frac{x}{5}=4\]\[\Rightarrow \]\[x=80\]

Hence, the distance between the two ports is 80 km.