A man can row at 4 kmph in still water. If the velocity of current is 2 kmph and it takes him 8 hour to row to a place and come back, how far is the place?
Let the distance be x km. Speed upstream = 4 – 2 = 2 kmph Speed downstream = 4 + 2 = 6 kmph => (x/6) + (x/2) = 8 => (x + 3x)/6 = 8 => 4x = 48 => x = 12 km
