A train 120 meters long passes a track worker walking at 6 km/h in the same direction in 12 seconds. What is the actual speed of the train? MCQ with Answer and Explanation
A train 120 meters long passes a track worker walking at 6 km/h in the same direction in 12 seconds. What is the actual speed of the train?
A. 48 km/h
B. 38 km/h
C. 42 km/h
D. 45 km/h
Answer: Option C
Solution (By JKSSB Mock Tests)
Relative speed = 120 / 12 = 10 m/s = 10 * (18/5) = 36 km/h. Since they move in the same direction, Relative Speed = Speed of train - Speed of worker => 36 = Speed of train - 6 => Speed of train = 42 km/h.
Explanation:
Upstream speed = 16 / 4 = 4 km/h. Upstream Speed = Speed in still water - Current speed => 4 = Speed in still water - 1 => Speed in still water = 5 km/h.
Explanation:
By 7:00 AM, the first person covers 30 * 2 = 60 km. Relative speed = 40 - 30 = 10 km/h. Time to meet = 60 / 10 = 6 hours. Distance from A = Speed of second person * Time = 40 * 6 = 240 km.
Explanation:
Let the total distance be 150 km. First part = 50 km; Time = 50/20 = 2.5 hours. Remaining part = 100 km; Time = 100/50 = 2 hours. Total distance = 150 km, Total time = 4.5 hours. Average speed = 150 / 4.5 = 1500 / 45 = 34.28 km/h.
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