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. |
You need to login to perform this action.
You will be redirected in
3 sec