Question
The speed of a boat in still water is 6 times the speed
of the stream. If the difference between the upstream and downstream speed of the boats is 30 km/hr, then find the time taken by the boat to travel 300 km in upstream.Solution
Let the speed of the stream be ‘x’ km/hr Therefore, speed of the boat in still water = 6x km/hr Upstream speed of the boat = 6x – x = 5x km/hr Downstream speed of the boat = x + 6x = 7x km/hr According to the question, 7x – 5x = 30 => 2x = 30 => x = 15 Therefore, upstream speed of the boat = 5x = 75 km/hr Required time taken = 300/75 = 4 hours
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