Question 186957
Let the velocity of boat in still water  = b and velocity of river = r
Downstream velocity  =  b + r = 27/3 = 24 mph  
Upstream velocity = b – r = 60/10 = 10 mph
Adding the above two equations we get 2b = 24 + 10 = 34
So b  34/2 = 17 mph.  Plugging this value into the first equation we get 
17+ r = 24 ;  r = 24 – 17 = 7 mph

Answer is the river flows at 7 miles per hour and the boat goes in still water at the rate of 17 miles per hour




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