Final answer:
The average speed for a journey covering 1 km at 20 km/h and another 1 km at 30 km/h is calculated by dividing the total distance (2 km) by the total time taken (0.083 hours), resulting in an average speed of 24.1 km/h.
Step-by-step explanation:
To calculate the average speed of a journey where different speeds are used over equal distances, we must consider the total distance and the total time taken. The journey first covers a distance of 1 km at 20 km/h, and then another 1 km at 30 km/h.
First, let's find out how long it takes to cover each segment of the trip:
- Time for the first segment at 20 km/h: 1 km / 20 km/h = 0.05 hours.
- Time for the second segment at 30 km/h: 1 km / 30 km/h = 0.033 hours.
The total time is the sum of these times, which is 0.05 hours + 0.033 hours = 0.083 hours. The total distance is 2 km since both segments are 1 km each.
Now, we can calculate the average speed:
- Average speed = Total distance / Total time = 2 km / 0.083 hours = 24.1 km/h (rounded to one decimal place).
Therefore, the average speed for the entire journey is 24.1 km/h.