A person can row at 9 kmph and still water. He takes 8 1/2 hours to row from A to B and back. What is the distance between A and B if the speed of the stream is 1 kmph?	Options
A) 60 km  B) 87 km  C) 38 km  D) 67 km  E) 20 km
Let the distance between A and B be x km.   Total time = x/(9 + 1) + x/(9 - 1) = 8.5   =&gt; x/10 + x/8 = 17/2 =&gt; (4x + 5x)/40 = 17/2 =&gt; x   = 38 km.   Answer:38 km
<result>C</result>
A person can row at 9 kmph and still water. He takes 8 1/2 hours to row from A to B and back. What is the distance between A and B if the speed of the stream is 1 kmph?