Question
The speed of a boat in still water is 20 km/hr. If the
boat covers 80 km in upstream in 8 hours, then find the time taken by the boat to travel 150 km in downstream.Solution
Let the speed of the boat in still water and the speed of the current be ‘x’ km/hr and ‘y’ km/hr, respectively Upstream speed of the boat = (x – y) = 80/8 = 10 km/hr Or, 20 – y = 10 Or, y = 20 – 10 = 10 km/hr Therefore, downstream speed of the boat = 20 + 10 = 30 km/hr Required time taken = 150/30 = 5 hours
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