To determine the average speed of the car during its trip, 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 to the east. 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: \[ v = \frac{150 \text{ km}}{2 \text{ h}} = 75 \text{ km/h} \] 5. **Conclusion**: The average speed of the car during its trip is 75 km/h. ### Correct Option: The correct answer is **B. 75 km/h**. ### Explanation of Other Options: - **A. 50 km/h**: This option is incorrect because if the average speed were 50 km/h, the car would take longer to cover 150 km. Specifically, it would take: \[ \text{Time} = \frac{150 \text{ km}}{50 \text{ km/h}} = 3 \text{ hours} \] This is not consistent with the given time of 2 hours. - **C. 100 km/h**: This option is also incorrect. If the average speed were 100 km/h, the time taken would be: \[ \text{Time} = \frac{150 \text{ km}}{100 \text{ km/h}} = 1.5 \text{ hours} \] Again, this does not match the 2 hours stated in the problem. - **D. 150 km/h**: This option is incorrect as well. If the car traveled at 150 km/h, the time taken would be: \[ \text{Time} = \frac{150 \text{ km}}{150 \text{ km/h}} = 1 \text{ hour} \] This is significantly less than the 2 hours mentioned. ### Common Pitfalls: - **Confusing Speed with Time**: Students sometimes confuse the relationship between speed, distance, and time. Remember that average speed is calculated by dividing distance by time, not the other way around. - **Ignoring Units**: Always ensure that the units are consistent. In this case, both distance and time were in kilometers and hours, respectively, which is appropriate for calculating speed in km/h. ### Revision Summary: - Average speed is calculated using the formula: \( v = \frac{\text{Distance}}{\text{Time}} \). - For a distance of 150 km and a time of 2 hours, the average speed is 75 km/h. - Always check that your calculated speed aligns with the time taken for the journey. - Be cautious of unit consistency when performing calculations.