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: \[ v = 75 \text{ km/h} \] ### Conclusion: The average speed of the car during its journey is **75 km/h**. Therefore, the correct option is **B**. ### Explanation of Other Options: - **Option A (50 km/h)**: This option is incorrect because it suggests that the car traveled at a much slower speed than it actually did. If the average speed were 50 km/h, the car would take 3 hours to cover 150 km, which contradicts the given time of 2 hours. - **Option C (100 km/h)**: This option is also incorrect. If the car traveled at an average speed of 100 km/h, it would cover 200 km in 2 hours, which is more than the actual distance of 150 km. - **Option D (150 km/h)**: This option is incorrect as well. If the car traveled at 150 km/h, it would cover 300 km in 2 hours, which again exceeds the actual distance traveled. ### Common Pitfalls: - **Misunderstanding Average Speed**: Some students confuse average speed with instantaneous speed. Average speed is calculated over the entire journey, while instantaneous speed is the speed at a specific moment. - **Incorrect Unit Conversion**: Ensure that the units for distance and time are consistent. In this case, 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 units are consistent when calculating speed. - Be careful not to confuse average speed with instantaneous speed.