Friday, 16 December 2016

Question of the day 17-12-2016

Question of the day:

A person can row 750 meters  against the stream in 11 ¼ minutes and returns in 7 ½ minutes. The speed of the person in in still water is :

 a) 2 km/hr         b)3 km/hr         c)4km/hr          d) 5 km/hr
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1 comment:

  1. Bhaskar Reddy21 December 2016 at 08:51

    Answer: Option D
    Explanation:
    as 750 metres,
    and 11 1/4 minutes as 675 seconds.
    and 7 1/2 minutes as 450 seconds
    Rate upstream =(750/675)m/sec
    =10/9
    Rate downstream =(750/450) m/sec
    = 5/3
    Rate in still water =1/2{(10/9)+(5/3)} m/sec
    =25/18 m/sec
    ={(25/18)*(18/5)} km/hr
    =5 km/hr

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