Final answer:
To find the average speed of the round trip, we can use the formula: Average speed = Total distance / Total time. In this case, the average speed of the round trip is 32 km/h.
Step-by-step explanation:
To find the average speed of the round trip, we can use the formula:
Average speed = Total distance / Total time
In this case, the total distance of the round trip is twice the distance to work, which is 2 * 80 km = 160 km. The total time is the sum of the time taken to drive to work and the time taken for the return trip. Given that the average speed to work is 80 km/h and the average speed for the return trip is 20 km/h, the total time can be calculated as follows:
Total time = Distance to work / Average speed to work + Distance for return trip / Average speed for return trip = 80 km / 80 km/h + 80 km / 20 km/h = 1 hour + 4 hours = 5 hours
Now, we can substitute the total distance and total time into the formula to find the average speed:
Average speed = 160 km / 5 hours = 32 km/h
Therefore, the average speed of the round trip is 32 km/h.