A man can row at 5 kmph. in still water. If the velocity

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?

Let the distance be d km.
Speed upstream = 5 – 1 = 4 kmph S
peed downstream = 5 + 1 = 6 kmph

∴	d	+	d	= 1
	6		4

⇒	2d + 3d	= 1
	12

⇒ 5d = 12

⇒ d =	12	= 2.4 km
	5

Second method to solve this question :
Here, a = 5, b = 1

Average Speed =	(a + b)(a - b)
	a

Average Speed =	(5 + 1)(5 - 1)
	5

Average Speed =	24	= 4.8 kmph
	5

Distance =	1	× 4.8 = 2.4 kmph
	2