Excluding stoppages, the average speed of a bus is 60 km/hr and including stoppages, the average speed of the bus is 35 km/hr. For how many minutes does the bus stop per hour?  Pick one
A) 22
B) 88
C) 24
D) 20
E) 99

Rationale: "in 1 hr , the bus covers 60 km without stoppages and 35 km with stoppages . stoppage time = time take to travel ( 60 - 35 ) km i . e 25 km at 60 km / hr . stoppage time = 25 / 60 hrs = 24 min . answer : c"
Answer: C