A thief is stopped by a policeman from a distance of 500 metres. When the policeman starts the chase, the thief also starts running. Assuming the speed of the thief as 10km/h and that of the policeman as 18km/h, how far would the thief have run before he is overtaken?

Given:
Initial distance between policeman and thief =500 m=0.5 km
Speed of thief =10km/h
Speed of policeman =18km/h

Since both are running in the same direction, their relative speed is:

Relative Speed=18−10=8km/h
Time taken by the policeman to catch the thief:

Time=
Relative Speed
Initial Distance
​
=
8km/h
0.5 km
​
=
16
1
​
 hours
Distance covered by the thief in this time:

Distance=Speed of Thief×Time
Distance=10km/h×
16
1
​
 h=
16
10
​
 km=
8
5
​
 km
Converting distance into metres:

Distance=
8
5
​
×1000 m=5×125=625 metres