Practicing Success
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? |
12 24 30 28 |
28 |
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
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