A courier covers 40 km of his shift route at 20 km/h and the remaining 60 km at 30 km/h. Find his average speed across the whole shift. MCQ with Answer and Explanation
A courier covers 40 km of his shift route at 20 km/h and the remaining 60 km at 30 km/h. Find his average speed across the whole shift.
A. 24 km/h
B. 26 km/h
C. 28 km/h
D. 25 km/h
Answer: Option D
Solution (By JKSSB Mock Tests)
Total distance = 40 + 60 = 100 km. Time for first sector = 40 / 20 = 2 hours. Time for second sector = 60 / 30 = 2 hours. Total time = 4 hours. Average speed = 100 / 4 = 25 km/h.
A train leaves a station at 4:00 PM and travels at an average speed of 60 km/h. Another train leaves the same station at 5:00 PM in the same direction at an average speed of 80 km/h. At what time will the second train catch up with the first train?
Explanation:
By 5:00 PM, the first train has traveled for 1 hour and covered 60 km. Relative speed = 80 - 60 = 20 km/h. Time needed to catch up = 60 / 20 = 3 hours. Catch up time = 5:00 PM + 3 hours = 8:00 PM.
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