A thief started running after seeing a policeman at a distance of 225 m. Instantly, the policeman started chasing the thief. The thief and the police ran at the rate of 9 km/h and 10 km/h respectively. Find the distance between them after 4.2 min.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 155 m.
Speed = Distance/time
Distance between police and thief = 225 m
Speed of policeman = 10 km/h
Speed of thief = 9 km/h
Relative speed in the same direction = Speed of Policeman - Speed of thief
= 10 - 9 = 1 km/h
So, 1 km or 1000 meter distance covered in 1 hour
1000 m = 60 min
Distance covered in 4.2 min = 1000/60 × 4.2 = 70 meters
The distance between them after 4.2 min = 225 - 70 = 155 meters