Correct option is A
Let the total distance be 200 km.The car breaks down at half the journey, so the car travels 100 km.The speed of the car is 40 km/hr.The time taken by the car to travel 100 km is:Time=SpeedDistance=40100=2.5 hoursThe remaining distance is also 100 km. The total time taken to reach the destination is 4.5 hours.The time taken by the bus is:Time (bus)=Total time−Time (car)=4.5−2.5=2 hoursThe distance travelled by the bus is 100 km.Speed of the bus=TimeDistance=2100=50 km/hrTherefore, the speed of the bus is 50 km/hr.