Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour?  Choose the correct choice from the following choices:
A) 7 min
B) 8 min
C) 9 min
D) 10 min
E) 11 min
Due to stoppages, it covers 9 km less.   Time taken to cover 9 km =(9/54)x60 = 10 min   answer : 10 min
<result>D</result>
Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour?