Excluding stoppages, the speed of a bus is 54 km/hr. and

Excluding stoppages, the speed of a bus is 54 km/hr. and including stoppages it is 45 km/hr. for how many minutes does the bus stop per hour ?

Due to stoppages, it covers 9 km. less per hour

Required time = Time taken to cover 9 km.
= 9 / ( 54 /60) min
= 10 min