Question

A car can travel the distance between the station and the post-office, which are 1.2 Km apart , in 1.8 minutes. How much faster must it travel to do the distance in 1.5 minutes?

Answer 1

he covers 1200 m in 108 seconds so:
speed is 11.11 m/s 
then ,   time is 90 seconds ( 1.5 minutes)
1200 in 90 seconds so:
speed is 13.33 m/s
difference is 2.22 m/s
it is 7.992 km/h
so approximately 8 km/h