The problem states:

• For the first 2 hours, the car traveled at a speed of 65.2 km/h.
• For the next 3 hours, the car traveled at 72 km/h.
• For the last hour, the car traveled at 80.5 km/h.

We are asked to find the average speed of the car over the entire journey.

Step-by-step solution:

1. Calculate total distance for each segment:

   • Distance in the first 2 hours:
     $d_1 = 65.2 \, \text{km/h} \times 2 \, \text{h} = 130.4 \, \text{km}$
   • Distance in the next 3 hours:
     $d_2 = 72 \, \text{km/h} \times 3 \, \text{h} = 216 \, \text{km}$
   • Distance in the last hour:
     $d_3 = 80.5 \, \text{km/h} \times 1 \, \text{h} = 80.5 \, \text{km}$

2. Calculate total distance: $\text{Total distance} = d_1 + d_2 + d_3 = 130.4 + 216 + 80.5 = 426.9 \, \text{km}$

3. Calculate total time: $\text{Total time} = 2 + 3 + 1 = 6 \, \text{hours}$

4. Calculate average speed: $\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} = \frac{426.9}{6} \approx 71.15 \, \text{km/h}$

Answer:

The average speed of the car over the entire journey is approximately 71.15 km/h.

Would you like more details on any part of the solution, or have any questions?

Related questions:

1. How is average speed calculated for a trip with multiple speed segments?
2. What is the difference between average speed and instantaneous speed?
3. How can you calculate the average speed when distance rather than time is given for each segment?
4. How would the result change if the time for each segment varied more significantly?
5. What factors could affect the average speed of a vehicle in real-life conditions?

Tip:

Always ensure that the units for distance and time are consistent (e.g., kilometers and hours) when calculating average speed.