Aptitude Discussion

Q. |
Rahul can row a certain distance downstream in 6 hour and return the same distance in 9 hour. If the speed of Rahul in still water is 12 km/hr, Find the speed of the stream. |

✖ A. |
2 km/hr |

✔ B. |
2.4 km/hr |

✖ C. |
3 km/hr |

✖ D. |
1.5 km/hr |

**Solution:**

Option(**B**) is correct

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

Thus, downward stream = $(12+x)$

and upward stream = $(12−x)$

suppose the distance travelled be $y$, Given:

\(\dfrac{y}{12+x}=6\) and \(\dfrac{y}{12-x}=9\)

On solving these two equations we get:

$x$ = **2.4 km/hr**