Final answer:
The average temperature during the period from 9 am to 9 pm is calculated using five temperature readings taken at equal intervals over that time span, leading to the formula Tave = (T9am + T12pm + T3pm + T6pm + T9pm) / 5.
Step-by-step explanation:
To find the average temperature Tave during the period from 9 am to 9 pm, we need to consider all temperature measurements taken at equal intervals within this time span. If we have temperature readings at 9 am, 12 pm, 3 pm, 6 pm, and 9 pm, each of these points should contribute to the calculation of Tave. Hence, the correct formula to determine Tave is option B.
The formula is as follows:
Tave = (T9am + T12pm + T3pm + T6pm + T9pm) / 5
This formula averages the temperatures recorded at five equally spaced points in time, giving us an accurate representation of the average temperature over the 12-hour period.