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?  Choose the correct option:
A) 22	B) 10	C) 99	D) 77	E) 29
Due to stoppages, it covers 9 km less.   Time taken to cover 9 km = 9/54 * 60= 
<gadget id="calculator">9/54 * 60</gadget>
<output>10</output>
10 min.   Answer:10
<result>B</result>
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?