A boat takes 19 hours for travelling downstream fro poin A to point B and coming back to a point C midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B?  Select
A) 180 km  B) 190 km  C) 220 km  D) 230 km  E) None
Sol.   Speed downstream = (14 + 4) km/hr = 18 km/hr;   Speed upstream = (14 - 4) km/hr = 10 km/hr.   Let the distance between A and B be x km. Then,   x/18 + (x/2)/10 = 19 ⇔ x/18 + x/20 = 19 ⇒ x = 180 km.   180 kmnswer 180 km
<result>A</result>
A boat takes 19 hours for travelling downstream fro poin A to point B and coming back to a point C midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B?