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 choice from the following options:
A) 15 min  B) 10 min  C) 17 min  D) 20 min  E) 30 min
D   10 min   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.
<result>D</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?