In a race, an athlete covers a distance of 438 m in 146 seconds in the first lap. He covers the second lap of the same length in 73 seconds. What is the average speed (in m/s) of the athlete?

P takes 6 hours more than Q to walk 'm' km. If P doubles his speed, then he can make it in 2 hours less than Q. How much time (in hours) does P require to walk 'm' km?

A policeman spots a thief from a distance of 105 metres. The thief and the policeman travel at speeds of 90 km/h and 100 km/h respectively. How long will it take the policeman to catch the thief?