A boat can travel with a speed of 10 km/hr in still water. If the speed of the stream is 8 km/hr, find the time taken by the boat to go 54 km downstream.  Select:  A) 4.25 hr  B) 5.25 hr  C) 3 hr  D) 2.25 hr  E) 2.50 hr

Rationale: "speed of boat in still water = 10 km / hr speed of the stream = 8 km / hr speed downstream = ( 10 + 8 ) = 18 km / hr time taken to travel 68 km downstream = 54 â  „ 18 = 17 â  „ 4 = 3 hours answer is c"
Answer: C