Boats and Streams - General Aptitude

Q1:

What is the speed of the boat in still water? I. It takes 2 hours to cover the distance between A and B downstream. II. It takes 4 hours to cover the distance between A and B upstream.

A I alone sufficient while II alone not sufficient to answer

B II alone sufficient while I alone not sufficient to answer

C II alone sufficient while I alone not sufficient to answer

D Both I and II are not sufficient to answer

E Both I and II are necessary to answer

ANS:D - Both I and II are not sufficient to answer

Let AB = x km.

I. Speed downstream =	x	km/hr
	2

II. Speed upstream =	x	km/hr.
	4

Speed of boat in still water =	1		x	+	x	km/hr.
	2		2		4

Thus, I and II both even do not give the answer.

Correct answer is (D).