Final answer:
To find out what time the plane left Edinburgh airport, calculate the duration of the flight by dividing the distance by the average speed. The plane's flight took approximately 1.333 hours, which is 80 minutes. Subtracting this from the arrival time of 20:15, we find that the plane left at 18:55 on the 24-hour clock.
Step-by-step explanation:
The subject of this question is Mathematics, specifically focusing on the topic of time and speed calculations which is commonly covered in High School curriculum.
To calculate the time the plane left Edinburgh airport, we need to use the formula for time, which is Time = Distance / Average Speed. In this scenario, the plane flew 232 miles at an average speed of 174 mph. Therefore, the time taken for the journey is 232 miles / 174 mph = 1.333 hours. Since the plane arrived at 20:15 (8:15 PM), we need to subtract the duration of the flight from the arrival time. Converting 1.333 hours to minutes gives us approximately 80 minutes (1 hour and 20 minutes). Subtracting 1 hour and 20 minutes from 20:15 gives us 18:55, or 6:55 PM on the 24-hour clock. Thus, the plane left Edinburgh at 18:55.