A policeman saw a thief from distance of 450m and started running towards him. If speed of policeman and thief are 23 km/hr and 20 km/hr respectively , the distance covered by thief before he is being caught is:

3 km

         P                      T

         Ι------------------Ι---------------Ι

                450 m

Speed (T) = 20km/h

Speed (P) = 23km/h

Relative speed = (23 - 20) km/h = 3km/h = 3 × \(\frac{5}{18}\) m/sec

Now,

Time = \(\frac{450}{{3} × \frac{5}{18}} \) = 540 sec

Distance (T) = 20 × \(\frac{5}{18}\) × 540 = 3000 m = 3 km