A person starting from his house covers a distance at 15 km/hr and returns to the starting place at 10 km/hr. His average speed during whole journey is

 

  • Option 1)

     

    11 km/hr  

     

  • Option 2)

     

    12 km/hr    

     

  • Option 3)

     

    7\frac{1}{2}km/hr

     

  • Option 4)

     

    10 km/hr

     

  • Option 5)

     

    13 km/hr

     

Answers (1)

Average speed = (2xy)/(x+y)   

                          = (2 x 15 x 10)/ (15+10) => 12k/hr

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