Question

a boat takes 12 min less when rowing downstream than when rowing upstream in a river between 2 points on a river. find the speed of the boat in still water and the speed of the current of the river (i know this sounds impossible write the answer if u know dont write that the question is wrong)

Answer 1

Solution:

Let the speed of boat in still water = x km/hr

Speed of Stream = y km/hr

Speed of Boat while going Downstream = (x +y) Km/hr

Speed of Boat while going Upstream =(x-y) Km/hr

Let Total Distance between two points = S Km

Also, it is given that the boat takes 12 minutes less when Rowing Downstream , than when rowing upstream.

Converting the above Written equation in terms of equation

$\frac{S}{x-y}-\frac{S}{x+y}=\frac{12}{60}\\\\5\times S[x+y-(x-y)]=(x+y)(x-y)\\\\x^2-y^2=10 S$

As, All, x>0,y>0 and ,S>0.

As, distance between two points is not given, Neither Speed of boat, nor Speed of stream is given.

So, there are three variables in the above equation that is

x²-y²=10 S, Means three Unknowns and Single Equation.

So, Neither, the speed of the boat in still water nor the speed of the current of the river can be calculated from the given Information.