River is running at 2 kmph. It took a man twice as long

River is running at 2 kmph. It took a man twice as long to row up as to row down the river. The rate (in km ph) of the man in still water is :

Let rate upstream be y kmph.
Then, rate downstream = 2y kmph

∴ Rate of current =	1	(2y - y) =	y	kmph
	2		2

∴	y	= 2 ⇒ y = 4
	2

∴ Rate upstream = 4 kmph
Rate downstream = 8 kmph

∴ Rate in still water =	1	(8 + 4) = 6 kmph
	2