A worker covers 40% of his path at 20 km/h and the remaining 60% at 30 km/h. Find his average speed for the full journey. MCQ with Answer and Explanation
A worker covers 40% of his path at 20 km/h and the remaining 60% at 30 km/h. Find his average speed for the full journey.
A. 24 km/h
B. 26 km/h
C. 28 km/h
D. 25 km/h
Answer: Option D
Solution (By JKSSB Mock Tests)
Let total distance be 100 km. First section = 40 km; Time = 40 / 20 = 2 hours. Second section = 60 km; Time = 60 / 30 = 2 hours. Total time = 4 hours. Average speed = 100 / 4 = 25 km/h.
Explanation:
Speed of B = 600 / 75 = 8 m/s. Distance covered by B when A crosses the finish line at 66 seconds = 8 * 66 = 528 meters. Winning margin = 600 - 528 = 72 meters.
A suspect flees at 6:00 AM at a uniform speed of 50 km/h. The enforcement squad tracks pursuit at 7:00 AM at 60 km/h. At what time will the squad apprehend the suspect?
Explanation:
By 7:00 AM, the suspect has traveled for 1 hour and covered 50 km. Relative tracking speed = 60 - 50 = 10 km/h. Time taken to catch = 50 / 10 = 5 hours. Apprehension time = 7:00 AM + 5 hours = 12:00 PM.
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