If a women goes 18 km downstream in 4 hrs and returns against the stream in 12 hrs, then the speed of the stream in Km/hr is
Answer & explanation
Correct answer: option 3
Speed of boat in still water - x
Speed of stream/current - y
Downstream speed i.e. x + y = \(\frac{18 }{ 4}\) = 4.5 km/hr ----(1)
Upstream speed i.e. x - y = \(\frac{18 }{ 12}\) = 1.5 km/hr -----(2)
Subtracting 2 from 1
x + y - ( x - y ) = 4.5 - 1.5
x + y - x + y = 3
2y = 3
y = 1.5 km/hr