Answers

2014-12-28T17:47:39+05:30
Let x km/minute be the velocity of flow
                         and speed of boat in still water= y km/minute
let after time=t minutes it passes the raft
The travel time of raft is (60+t) minutes
       and the distance traveled is (60+t)*x = 6
                                             t = 6/x-60
From the question 60(x+y) - t(y-x) = 6
                           60x + 60y - (6/x - 60)(y - x) = 6
                       ⇒  60x + 60y - 6y/x + 60y + 6 - 60x = 6
                       ⇒ 120y - 6y/x=0
                       ⇒  20y=y/x
                           x=1/20=1/20 km/minute= 3km/hr
                          
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jhan se copy and paste kiya vo site
https://books.google.co.in/books?id=Yp6gBq4lXEgC&pg=PA170&lpg=PA170&dq=A+motorboat+going+downstream+overcame+a+raft+at+a+point+A;t+%3D+60+min+later+it+turned+back+and+after+some+time+passed+the+raft+at+a+distance+l+%3D+6.0+km&source=bl&ots=XTbLmEEYEj&sig=yrmIHatyiKOMxx8QmG84lhxdCYE&hl=en&sa=X&ei=qPifVIK7CY6ZuQT5z4LoCQ&ved=0CCMQ6AEwAQ#v=onepage&q=A%20motorboat%20going%20downstream%20overcame%20a%20raft%20at%20a%20point%20A%3Bt%20%3D%2060%20min%20later%20it%20turned%20back%20and%20after%20some%20t
ka adress ok
thankyou
answer to delete kr do dekh kr bhi theek se nhi likh te