A boat can travel 60 km downstream in 4 hours. If the speed of the boat in still water is 13 km/h, then in what time will it cover 30 km upstream?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. hours.
Let the speed of the stream be x km/h.
Speed of the boat downstream = (13 + x) km/h.
Distance = 60 km, Time = 4 hours.
Speed = Distance/Time.
⇒ 13 + x = 60/4
⇒ 13 + x = 15
⇒ x = 15 - 13
x = 2 km/h
Speed of the boat upstream = (13 - 2) km/h = 11 km/h.
Distance = 30 km, Speed = 11 km/h.
Time = Distance/Speed.
Time = 30/11 hours. Time ≈ 2.73 hours.
Therefore, the boat will cover 30 km upstream in approximately 2.73 hours.
The answer is 2.73 hours.