Final answer:
The average hours of sleep Peter got over the three days, after converting Wednesday's minutes to hours, is 8 hours.
Step-by-step explanation:
Peter slept for 8 hours on Monday, 9 hours on Tuesday, and 420 minutes on Wednesday.
To calculate the average hours of sleep over these three days, first convert Wednesday's sleep time from minutes to hours by dividing 420 by 60, which equals 7 hours. Then, add the sleep hours for the three days together (8+9+7 = 24 hours) and divide by the number of days (3) to find the average.
The average hours of sleep Peter got during these three days is 8 hours.