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 one
A) 70 min  B) 16 min  C) 20 min  D) 10 min  E) 40 min
D   10 min   Due to stoppages, it covers 9 km less.   Time taken to cover 9 km = (9/54 x 60) min = 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?