Explanation:

To calculate the average speed for the entire journey, we need to find the total distance covered and the total time taken.

- Total Distance:

- 275 km + 315 km = 590 km

- Time for first part of journey:

- Distance = 275 km

- Speed = 50 km/h

- Time = Distance/Speed = 275 / 50 = 5.5 hours

- Time for second part of journey:

- Distance = 315 km

- Speed = 70 km/h

- Time = Distance/Speed = 315 / 70 = 4.5 hours

- Total Time:

- 5.5 hours + 4.5 hours = 10 hours

- Average Speed:

- Total Distance / Total Time = 590 km / 10 hours = 59 km/h

Given the options:

- Option 1: 58.5

- Option 2: 60

- Option 3: 59

- Option 4: 62

Correct Answer: Option 3, 59