If the probability of drawing an ace from a deck of cards is 0.077 and the probability of rolling a "2" using a fair die is 0.167, then the probability of drawing an ace and rolling a "2" is

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?