$$ \text{h} $$Zak drove his car at an average speed of 80 km/h for the first 60 km. Then, he drove his car at an average speed of 102 km/h for the next 2 hours. find the average speed of the whole journey in km/h.

To find the average speed of the entire journey, we need to use the formula:

\[
\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}}
\]

### Step 1: Calculate the total distance traveled
- In the first part of the journey, Zak drove 60 km.
- In the second part of the journey, he drove at 102 km/h for 2 hours.

So, the distance covered in the second part is:

\[
\text{Distance}_2 = 102 \, \text{km/h} \times 2 \, \text{hours} = 204 \, \text{km}
\]

Thus, the total distance is:

\[
\text{Total Distance} = 60 \, \text{km} + 204 \, \text{km} = 264 \, \text{km}
\]

### Step 2: Calculate the total time taken
- For the first part, the time taken is calculated as:

\[
\text{Time}_1 = \frac{\text{Distance}_1}{\text{Speed}_1} = \frac{60 \, \text{km}}{80 \, \text{km/h}} = 0.75 \, \text{hours}
\]

- For the second part, Zak took 2 hours, as given.

So, the total time is:

\[
\text{Total Time} = 0.75 \, \text{hours} + 2 \, \text{hours} = 2.75 \, \text{hours}
\]

### Step 3: Calculate the average speed
Now, using the formula for average speed:

\[
\text{Average Speed} = \frac{264 \, \text{km}}{2.75 \, \text{hours}} = 96 \, \text{km/h}
\]

Thus, the average speed for the whole journey is **96 km/h**.

Would you like more details on any step or have questions?

Here are some related questions to explore:
1. How does changing the second part of the journey's speed affect the average speed?
2. What if Zak had driven the first part at 100 km/h instead of 80 km/h?
3. How does the total distance affect the average speed?
4. If Zak took a break for 30 minutes during the journey, how would this impact the calculation?
5. How can we calculate average velocity if Zak changed direction during the journey?

**Tip**: Remember, average speed depends only on total distance and total time, not on how the speed varies at different parts of the journey!

Zak drove his car at an average speed of 80 km/h for the first 60 km. Then, he drove his car at an average speed of 102 km/h for the next 2 hours. Find the average speed of the whole journey in km/h.

Learn how to calculate the average speed of a journey where Zak drives at different speeds over two parts. He first drives 60 km at 80 km/h and then continues for 2 hours at 102 km/h. Find the average speed step-by-step using distance-time relationships. Suitable for Grades 6-8.

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