Final answer:
The correct inequality to find the number of hours (x) after which the temperature will measure below -3 Celsius is 12x ≤ -3 (option C), assuming a consistent hourly decrease in temperature starting at noon.
Step-by-step explanation:
To determine the inequality that represents the number of hours (x) after which the temperature will measure below -3 Celsius in Toronto, we must understand the rate of temperature change per hour. Let's assume the initial temperature at noon (T0) is given and the rate of temperature drop per hour is constant. For a temperature to be lower than -3 Celsius after x hours, we could represent this situation as T0 - kx < -3, where k is the rate of temperature decrease per hour.
If we were considering the measurement as accurate from the 12th hour (noon), a drop in temperature by x hours would be represented as 12-x < -3. However, since the question states that the temperature started dropping every hour, we need an inequality that shows the temperature will be less than -3 Celsius after a certain number of hours have passed. Therefore, the correct inequality must be of the form Temperature < -3 after x hours. This corresponds to option C) 12x ≤ -3 since we are looking for the time when the temperature first reaches below -3 degrees Celsius, including exactly at the time it reaches that temperature.