A policeman spots a thief at a distance of 200 m and starts chasing him. While the policeman runs at a speed of 9 km/ h, the thief runs at a speed of 7 km/ h. After how long will the policeman catch the thief?

6 minutes

Relative speed of thief and police = 9 - 7 = 2 km/h = \(\frac{5}{9}\) m/sec

Distance b/w them = 200 m

Time taken by police to caught thief = \(\frac{200 × 9 }{5}\) = 360 seconds

360 seconds = \(\frac{360}{60}\) min  = 6 minutes ( 1 min = 60 sec)