A crew can row a certain course up the stream in 84 minutes; they can row the same course down stream in 8 minutes less than they can row it in still water. How long would they take to row down with the stream  Choose one.
A) 45 or 23 minutes B) 63 or 12 minutes C) 76 minutes D) 19 minutes E) 25 minutes
A method has been discussed here to nullify the calculations though.   All I can input here is,   speed of a crew in still water = 1/2 ( speed upstream + speed downstream)   approximating this for time,   t = 1/2(84+ (t-8))   giving t = 76   76 minutes.
<result>C</result>
A crew can row a certain course up the stream in 84 minutes; they can row the same course down stream in 8 minutes less than they can row it in still water. How long would they take to row down with the stream