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?
Options.
A) 10  B) 15  C) 20  D) 30  E) None
Sol.   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.   10nswer 10
<result>A</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?