Final answer:
To find the speed of the car from B to A, calculate the total distance (240 km), use the round trip average speed (50 km/hr) to find the total time (4.8 hours), subtract the time for A to B (2 hours) to get the B to A time (2.8 hours), and finally divide the distance by the time to get the speed (42.86 km/hr).
Step-by-step explanation:
To calculate the speed of the car when it moves from town B to A, we will first determine the total distance traveled and then use the average speed for the round trip to calculate the time taken.
The car moves with a steady speed of 60 km/hr for 2 hours from A to B. Therefore, the distance from A to B is:
- Distance = Speed x Time
- Distance = 60 km/hr x 2 hours
- Distance = 120 km
Since the trip from B to A is the same distance, the total distance for the round trip is 240 km.
The average speed for the round trip is given as 50 km/hr. We can use this to calculate the total time for the round trip and then find the time taken for the return trip.
- Total time = Total distance / Average speed
- Total time = 240 km / 50 km/hr
- Total time = 4.8 hours
Since the trip from A to B took 2 hours, the trip from B to A must have taken 4.8 hours - 2 hours = 2.8 hours.
Now, we can determine the speed from B to A using the distance of the return trip and the time calculated:
- Speed = Distance / Time
- Speed = 120 km / 2.8 hours
- Speed ≈ 42.86 km/hr
The speed of the car when it moves from town B to A is approximately 42.86 km/hr.