A boat covers a certain distance downstream in I hour, while it comes back in 1½ hours. If the speed of the stream be 3 kmph. what is the speed of the boat in still Water?  Pick one:
A) 12kmph  B) 13kmph  C) 15kmph  D) 16kmph  E) None
Solution   Let the speed of the boat in still water be x kmph. Then,   Speed downsteram	= (x + 3) kmph.   Speed upsteram	= (x - 3) kmph.   = (x+3)x1   = (x - 3)x3/2 kmph.   = 2x+6 = 3x-9   x= 15 kmph.   Answer 15kmph
<result>C</result>
A boat covers a certain distance downstream in I hour, while it comes back in 1½ hours. If the speed of the stream be 3 kmph. what is the speed of the boat in still Water?