A commuter drives to his consulting firm at 30 km/h and arrives 15 minutes late. If he increases his speed to 40 km/h, he arrives 5 minutes early. Find the distance to his firm. MCQ with Answer and Explanation
A commuter drives to his consulting firm at 30 km/h and arrives 15 minutes late. If he increases his speed to 40 km/h, he arrives 5 minutes early. Find the distance to his firm.
A. 50 km
B. 40 km
C. 45 km
D. 35 km
Answer: Option B
Solution (By JKSSB Mock Tests)
Time difference = 15 - (-5) = 20 minutes = 20/60 = 1/3 hours. Let distance be d. d/30 - d/40 = 1/3 => (4d - 3d)/120 = 1/3 => d/120 = 1/3 => d = 40 km.
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