A boat takes 8 hrs to cover a distance while travelling upstream whereas while travelling downstream, it takes 6 hrs. if the speed of the current is 4 Km/hr, what is the speed of the boat in still water in Km/hr?
Answer & explanation
Correct answer: option 4
Speed of current i.e. y = 4km/hr
Speed of boat in still water i.e. x = ?
Downstream speed = x + y
Upstream speed = x - y
Speed = \(\frac{ Distance}{ Time}\)
Distance = Speed x Time
According to the question:
Distance = Downstream speed x 6
Distance = (x + y) 6 ------------(1)
Distance = Upstream speed x 8
Distance = (x - y) 8 -------------(2)
From 1 and 2 equation, we can deduce:
6 (x + y) = 8 (x - y)
6( x + 4) = 8 ( x - 4)
6x + 24 = 8x - 32
2x = 56
x = 28 km/hr