Answer:
70 km/h
Step-by-step explanation:
The average speed is given by combining the two speeds and dividing them by two
Given
Speed to office as 57 km/h
Speed to house as 83 km/h
The differences in speeds may be due to the terrain of the land
Total speed is 57+83=140 km/h
Average speed is 140/2=70 km/h
Therefore, on average, the car went on a journey at the spees of 70 km/h