A person reaches his destination 40 minutes late if his speed is 3 km/h, and reaches 30 minutes early if his speed is 4 km/h. Find the distance to his destination. MCQ with Answer and Explanation
A person reaches his destination 40 minutes late if his speed is 3 km/h, and reaches 30 minutes early if his speed is 4 km/h. Find the distance to his destination.
A. 12 km
B. 16 km
C. 15 km
D. 14 km
Answer: Option D
Solution (By JKSSB Mock Tests)
Time difference = 40 - (-30) = 70 minutes = 70 / 60 = 7/6 hours. Let distance be d. d/3 - d/4 = 7/6 => d/12 = 7/6 => d = 14 km.
A sprinter tracks a 100-meter course in 10 seconds, while the runner-up completes it in 11 seconds. By what distance does the winner beat the runner-up?
Explanation:
New speed = 4/5 of usual speed => New time = 5/4 of usual time. Difference = 1/4 of usual time = 12 minutes. Usual time = 12 * 4 = 48 minutes.
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