1) A boat takes 19 h for travelling downstream from point A to point B and coming back to point C, midway between A and B. If velocity of the stream is 4 km/h and the speed of the boat in still water is 14 km/h. What is the distance between A and B ? A) 160 km B) 180 km C) 200 km D) 220 km E) 240 km Answer: Option BExplanation:Speed downstream $=14+4$ = 18 km/h Speed upstream $=14-4$ = 10 km/h Let the distance travelled between $A$ and $B$ be $x$ km Then $\frac{x}{18}+\frac{x/2}{10}$ = 19 $x$ = 180 km/h
