A man covers 50 km at a speed of 25 km/h and another 90 km at a speed of 30 km/h. Find his average speed for the whole journey. MCQ with Answer and Explanation
A man covers 50 km at a speed of 25 km/h and another 90 km at a speed of 30 km/h. Find his average speed for the whole journey.
A. 30 km/h
B. 28 km/h
C. 28.5 km/h
D. 26.5 km/h
Answer: Option B
Solution (By JKSSB Mock Tests)
Total distance = 50 + 90 = 140 km. Time for first part = 50 / 25 = 2 hours. Time for second part = 90 / 30 = 3 hours. Total time = 5 hours. Average speed = 140 / 5 = 28 km/h.
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?
Explanation:
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.
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