BIW{boat in water}
Classical Mechanics
Level
2
A boat takes 2 h to travel 8 km and back in still water, if the velocity of water is 4 km/h the time taken for going upstream 8 km and coming back is {in minutes}
The answer is 160.
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1 solution
As the total time taken is 2 hour to travel 8 km up & down; means 16 km in still water, so the actual velocity of the boat is (16/2)=8 km per hour. Then, if the velocity of water is 4 km per hour. Then, going "Down Stream", the resultant velocity is=(8+4)=12 km per hour. But, going "Up Stream" the resultant velocity is=(8-4)=4 km per hour. So, The Total time taken will be (8/12)+(8/4)=(32/12) hour= (32*60/12)=160 Minutes.