Question
A boat takes 20 hours to travel 260 km downstream. The
speed of the boat in still water is 125% greater than the speed of the stream. If the boat completes a round trip from point 'P' to point 'Q' and back to 'P' in 18 hours, determine the distance between points 'P' and 'Q'.Solution
Downstream speed of the boat = (260/20) = 13 km/hr Let the speed of the stream be '4x' km/hr So, speed of boat in still water = 4x X (2.25) = '9x' km/hr So, (4x + 9x) = 13 So, 13x =13 So, 'x' = 1 So, speed of the boat in still water = 9 km/h The upstream and downstream speed of the boat are 5 km/h and 13 km/h respectively. Let the distance between points 'P' and 'Q' be 'A' km. ATQ, (A/13) + (A/5) = 18 Or, (18A/65) = 18 So, 'A' = 65
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