Two junction points M and N are separated by 300 km. Train P leaves M for N at 45 km/h at 8:00 AM. Train Q leaves N for M at 55 km/h at 9:00 AM. At what time will they cross? MCQ with Answer and Explanation
Two junction points M and N are separated by 300 km. Train P leaves M for N at 45 km/h at 8:00 AM. Train Q leaves N for M at 55 km/h at 9:00 AM. At what time will they cross?
A. 12:00 PM
B. 11:15 AM
C. 11:45 AM
D. 11:33 AM
Answer: Option D
Solution (By JKSSB Mock Tests)
By 9:00 AM, Train P has tracked for 1 hour, covering 45 km. Remaining route segment gap separation = 300 - 45 = 255 km. Relative speed index = 45 + 55 = 100 km/h. Time after 9:00 AM = 255 / 100 = 2.55 hours = 2 hours 33 minutes. Meeting time is 11:33 AM.
Explanation:
Let current speed be c. Upstream speed = 8 - c, Downstream speed = 8 + c. Given: 3 * (8 - c) = 8 + c => 24 - 3c = 8 + c => 4c = 16 => c = 4 km/h.
A vehicle runs at an average speed of 54 km/h. It wraps the first half of the trip duration in 2 hours and the second half duration at 66 km/h. Find the time spent on the second half duration.
Explanation:
Since it specifies 'half of the trip duration', the time for both halves is identical. Time spent on the second half is equal to the first half, which is 2 hours.
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