Excluding stoppages, the average speed of a bus is 75 km/hr and including stoppages, the average speed of the bus is 40 km/hr. For how many minutes does the bus stop per hour?	Choose the correct choice from the following answers:  A) 15 min  B) 18 min  C) 16 min  D) 20 min  E) 28 min
In 1hr, the bus covers 75 km without stoppages and 40 km with stoppages.   Stoppage time = time take to travel (75 - 40) km i.e 35 km at 75 km/hr.   stoppage time = 35/75 hrs   = 28 min   Answer: 28 min
<result>E</result>
Excluding stoppages, the average speed of a bus is 75 km/hr and including stoppages, the average speed of the bus is 40 km/hr. For how many minutes does the bus stop per hour?