To determine the average speed of the car during its journey, we can use the formula for average speed, which is defined as the total distance traveled divided by the total time taken. ### Step-by-Step Explanation: 1. **Identify the Total Distance**: The car travels a total distance of 150 kilometers. 2. **Identify the Total Time**: The time taken for this journey is 2 hours. 3. **Use the Average Speed Formula**: The formula for average speed (v) is given by: \[ v = \frac{\text{Total Distance}}{\text{Total Time}} \] 4. **Substitute the Values**: Plugging in the values we have: \[ v = \frac{150 \text{ km}}{2 \text{ h}} \] 5. **Perform the Calculation**: Now, we perform the division: \[ v = 75 \text{ km/h} \] Thus, the average speed of the car during its journey is **75 km/h**. ### Why Option A is Correct: - **Correct Calculation**: The calculation shows that the average speed is indeed 75 km/h, which matches option A. - **Understanding Average Speed**: Average speed is a straightforward calculation based on total distance and total time, and in this case, both values are clearly defined. ### Why Other Options are Incorrect: - **Option B (60 km/h)**: This option suggests a lower average speed. If we were to calculate the average speed as 60 km/h, it would imply that the car traveled less distance in the same time, which contradicts the given distance of 150 km. - **Option C (100 km/h)**: This option indicates a higher average speed. If the car were traveling at 100 km/h for 2 hours, it would cover 200 km (100 km/h × 2 h), which is more than the actual distance of 150 km. Therefore, this option is not feasible. - **Option D (50 km/h)**: This option also suggests a lower average speed. If the car were traveling at 50 km/h for 2 hours, it would only cover 100 km (50 km/h × 2 h), which is again less than the actual distance traveled. ### Common Pitfalls: - **Confusing Average Speed with Instantaneous Speed**: Average speed is not the same as instantaneous speed, which can vary during the journey. Always remember to use total distance and total time for average speed calculations. - **Misreading Units**: Ensure that the units for distance and time are consistent. Here, both are in kilometers and hours, which is appropriate for calculating speed in km/h. ### Revision Summary: - Average speed is calculated using the formula: \( v = \frac{\text{Total Distance}}{\text{Total Time}} \). - For this problem, the average speed is \( 75 \text{ km/h} \). - Always check that your calculated speed makes sense with the given distance and time. - Be cautious of unit consistency and the difference between average and instantaneous speed.