A thief is spotted by a policeman from a distance of 100 m. The thief starts running and the policeman chases him. If the speed of thief and policeman are 21 km/h and 23 km/h, respectively, then how far will the thief have to run before he is over taken?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 1050 m.
Given that, distance between policeman and thief = 100 m
Speed of policeman = 23 km/h
Speed of thief = 21 km/h
Distance = Speed × Time
When two people are running in same direction, their relative speed is equal to the difference between their individual speeds.
Relative speed of policeman and thief = 23 - 21 = 2 km/h
Relative speed of policeman and thief in m/sec = = 5/9 m/sec
Time taken by policeman to overtake thief = 100/(5/9) = 180 sec
Distance travelled by thief = = 1050 m
Hence the thief have to run 1050 m before he is over taken.