A real estate agent drives from his house to an office at 10 km/h and arrives 12 minutes late. If he increases his speed to 15 km/h, he arrives 4 minutes early. Find the distance. MCQ with Answer and Explanation
A real estate agent drives from his house to an office at 10 km/h and arrives 12 minutes late. If he increases his speed to 15 km/h, he arrives 4 minutes early. Find the distance.
A. 8 km
B. 6 km
C. 10 km
D. 12 km
Answer: Option A
Solution (By JKSSB Mock Tests)
Time difference = 12 - (-4) = 16 minutes = 16/60 = 4/15 hours. Let distance be d. d/10 - d/15 = 4/15 => (3d - 2d) / 30 = 4/15 => d / 30 = 4/15 => d = 8 km.
Explanation:
Speed of the second locomotive = 480 / 4 = 120 km/h. Ratio is 5:6, so 6 parts = 120 km/h => 1 part = 20 km/h. Speed of the first locomotive = 5 parts = 5 * 20 = 100 km/h.
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