Solved UPSC CDS/OTA Question
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Q · Time, Speed and DistanceMedium · 45s
How many times will a 900 meter long train take to cross a man walking with a speed of 10 km/hr in the direction of the moving train if the speed of the train is 70 km/hr?
TopicTime, Speed and Distance
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained - no skipped algebra.
Relative speed = 70 − 10 = 60 km/hr = 60 × 1000 / 3600 = 16.67 m/s
Time to cross = 900 / 16.67 ≈ 54 seconds
Answer: The train will take 54 seconds to cross the man.
Final Answer: Option A - 54sec