Final answer:
It took 6 hours for the temperature to change by -12°F at a rate of -2°F per hour.
Step-by-step explanation:
The question asks how long it took for the temperature to change by -12°F, given that the rate of change was -2°F per hour. To find the duration of the temperature change, we simply divide the total change in temperature by the rate of change:
Duration = Total change in temperature ÷ Rate of change per hour
Duration = -12°F ÷ -2°F/hour
Duration = 6 hours
So, it took 6 hours for the temperature to decrease by -12°F at a constant rate of -2°F per hour.