Jack can row at 9 kmph and still water. He takes 6 hours to row from A to B and back. What is the distance between A and B if the speed of the stream is 3 kmph? Choose the correct choice:
A) 30 km B) 25 km C) 24 km D) 28 km E) 20 km
Let the distance between A and B be x km.   Total time = x/(9 + 3) + x/(9 - 3) = 6   =&gt; x/12 + x/6 = 6 =&gt; (x + 2x)/12 = 6 =&gt; x = 24 km.   ANSWER:24 km
<result>C</result>
Jack can row at 9 kmph and still water. He takes 6 hours to row from A to B and back. What is the distance between A and B if the speed of the stream is 3 kmph?