Two trains 100 meters and 120 meters long are running in the same direction at speeds of 72 km/h and 54 km/h respectively. In how much time will the faster train cross the slower train completely? MCQ with Answer and Explanation
Two trains 100 meters and 120 meters long are running in the same direction at speeds of 72 km/h and 54 km/h respectively. In how much time will the faster train cross the slower train completely?
A. 36 seconds
B. 48 seconds
C. 44 seconds
D. 40 seconds
Answer: Option C
Solution (By JKSSB Mock Tests)
Total distance = 100 + 120 = 220 meters. Relative speed = 72 - 54 = 18 km/h = 5 m/s. Time taken = 220 / 5 = 44 seconds.
A high-speed train covers a distance between two terminals at 300 km/h in 4 hours. At what speed must it travel to cover the same distance in 3 hours and 20 minutes?
A thief is spotted by a policeman from a distance of 200 meters. The thief runs at 10 km/h and the policeman chases him at 12 km/h. Find the distance covered by the thief before he is caught.
Explanation:
Relative speed = 12 - 10 = 2 km/h. Time to catch the thief = 0.2 km / 2 km/h = 0.1 hours. Distance covered by thief = Speed * Time = 10 km/h * 0.1 hours = 1 km = 1000 meters.
A man can walk a certain distance in 6 hours and ride back in 2 hours. If he rides both ways, he will save 2 hours. How much time will he take if he walks both ways?
Explanation:
Let W be walking time one way and R be riding time one way. W + R = 6 + 2 = 8 hours (total trip: walk one way, ride back). If he rides both ways, total time is 2R. He saves 2 hours, so 2R = 8 - 2 = 6 hours => R = 3 hours. From W + R = 8, W = 5 hours. Walking both ways takes 2W = 10 hours.
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