Without stoppage, Kalpana travels bus travels a certain distance with

Without stoppage, Kalpana travels bus travels a certain distance with an average speed of 60 km/hr, and with stoppage, it covers the same distance with an average speed of 45 km/hr. On an average, how many minutes per hour does the bus stop during the journey ? (a) 25 min (b) 30 min (c) 45 min (…)