Answers

2015-09-06T18:17:59+05:30
Time taken=9 hrs
speed of the river=3 km/hr
let the speed of the boat be x
speed upstream= x-3
distance=speed x time
             =(x-3) x 9
             =9x-27
speed downstream=x+3
time=distance/speed
       =9x-27/x+3
       
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