a boat can travel with a speed of 40 km / hr in still water . if the speed of the stream is 5 km / hr , find the time taken by the boat to go 45 km downstream .
"speed downstream = ( 40 + 5 ) km / hr = 45 km / hr . time taken to travel 45 km downstream = 45 / 45 hrs = 1 hrs . answer : a"
divide(45, add(40, 5))