A person walks from his residence to his office at 4 km/h and arrives 15 minutes late. If he increases his speed to 6 km/h, he still arrives 5 minutes late. Find the distance. MCQ with Answer and Explanation
A person walks from his residence to his office at 4 km/h and arrives 15 minutes late. If he increases his speed to 6 km/h, he still arrives 5 minutes late. Find the distance.
A. 2 km
B. 2.5 km
C. 1.5 km
D. 3 km
Answer: Option A
Solution (By JKSSB Mock Tests)
Time difference = 15 - 5 = 10 minutes = 10 / 60 = 1/6 hour. Let distance be d. d/4 - d/6 = 1/6 => d/12 = 1/6 => d = 2 km.
Explanation:
The second man covers 10 meters in 2 seconds, so his speed = 10 / 2 = 5 m/s. Total time taken by second man to complete 100m = 100 / 5 = 20 seconds. Since the winner beats him by 2 seconds, winner's time = 20 - 2 = 18 seconds.
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