Final answer:
To find the average speed over the trip, we calculate the distances covered in each time segment and sum them to get total distance. Total time spent driving is added together, excluding non-driving periods. Finally, average speed is total distance divided by total time, but the correct average is not listed among the provided options.
Step-by-step explanation:
To calculate the person's average speed for the entire trip, we first find the total distance traveled and the total time taken, excluding the time spent on eating lunch and buying goods since those do not contribute to the movement between the cities. We have three segments of the trip with different speeds and times. To calculate distances for each segment, we use the formula distance = speed × time. Remember to convert time from minutes to hours by dividing by 60.
- First segment: 100.0 km/h × (25.0 min / 60) = 41.67 km
- Second segment: 55.0 km/h × (17.0 min / 60) = 15.58 km
- Third segment: 45.0 km/h × (35.0 min / 60) = 26.25 km
Next, we add up all the distances to find the total distance: 41.67 km + 15.58 km + 26.25 km = 83.5 km.
Then, we calculate time for each segment and add them up to find total time: (25.0/60) h + (17.0/60) h + (35.0/60) h = 1.283 hours.
Finally, we calculate the average speed by dividing total distance by total time: 83.5 km / 1.283 h = 65.08 km/h.
Therefore, the correct answer is not listed among the provided options A) 44.7 km/h, B) 83.5 km/h, C) Both A and B, and D) 75.0 km/h.