# Boats and Streams- Aptitude Questions and Answers

 There is a road beside a river. two friends started from a place A, moved to a temple situated at another place B and then returned to A again. one of them moves on a cycle at a speed of 12 kmph, while the other sails on a boat at a speed of 10 kmph . if the river flows at the speed of 4 kmph , which of the two friends will return to place A first? A) Sailor B) Cyclist C) Both D) Data insufficient Correct Answer : Cyclist Explanation :Clearly, The cyclist moves both ways at a speed of 12 kmph Average speed of the cyclist = 12 kmph the boat sailor speed downstream = (10+4) = 14 kmph speed upstream =(10-4) = 6 kmph So, average speed of the boat sailor =[ 2*14*6]/[14+6] kmph =42/5 kmph =8.4 kmph Since, the average speed of the cyclist is greater 12 kmph> 8.4 kmph So, the cyclist return to A first. A boat takes 19 hrs for travelling downstream from point 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? A) 13.5 km/hr B) 16.5 km/hr C) 12 km/hr D) 8.25 km/hr Correct Answer : 12 km/hr Explanation :Speed in downstream = (14 + 4) km/hr = 18 km/hr Speed in 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 19x/180 = 19 x = 180 km Hence, the distence between A and B is 180 km