Question

A boatman goes 2 km against the current of the stream in 2 hour and goes 1 km along the current in 20 minutes. How long will it take to go 5 km in stationary water?

Answer 1

Answer:

2 hour 30 minutes

Step-by-step explanation:

we can calculate speed upstream = distance / time

                                                         =  2/ 2 = 1km/hr

and speed downstream = 1/(20/60) = 3 km/hr

thus speed in still water will be 1/2 x (3+1) = 2 km/hr

thus, time taken to travel 5 km in still water = 5/2 hr = 2.5 hr which is = 2 hr 30 minute

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