A thief escapes from police custody at 1:00 PM running at 45 km/h. The police discover the escape at 1:20 PM and start chasing him at 60 km/h. At what time will the police catch the thief? MCQ with Answer and Explanation
A thief escapes from police custody at 1:00 PM running at 45 km/h. The police discover the escape at 1:20 PM and start chasing him at 60 km/h. At what time will the police catch the thief?
A. 2:00 PM
B. 3:00 PM
C. 2:30 PM
D. 2:20 PM
Answer: Option D
Solution (By JKExamLibrary)
In 20 minutes (1/3 hour), the thief covers 45 * (1/3) = 15 km. Relative speed = 60 - 45 = 15 km/h. Time taken to catch = 15 / 15 = 1 hour. Catching time = 1:20 PM + 1 hour = 2:20 PM.
Explanation:
New speed = 5/7 of usual speed => New time = 7/5 of usual time. Difference = 2/5 of usual time = 12 minutes. 1/5 of usual time = 6 minutes => Usual time = 6 * 5 = 30 minutes.
A car covers a total distance of 240 km. It travels the first half of the distance at 40 km/h and the second half at 60 km/h. Find the average speed for the full journey.
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