A man can row at 5 kmph in still water. If the velocity of current is 1 kmph and it takes him 1 hour to row to a place and come back, how far is the place?
2.4 km
2.5 km
3 km
3.6 km
Explanation:
Speed downstream = (5 + 1) kmph = 6 kmph.
Speed upstream = (5 - 1) kmph = 4 kmph.
Let the required distance be $ x $ km.
Then,$ \dfrac{x}{6} $+$ \dfrac{x}{4} $= 1 |
$\Rightarrow$ 2$ x $ + 3$ x $ = 12
$\Rightarrow$ 5$ x $ = 12
$\Rightarrow x $ = 2.4 km.