Olaf buys 4 cans of soup at the store for a total of $5.00. Which equation represents the cost, y, in dollars, of buying x cans of soup, given that the cost is proportional to the number of cans of soup?

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?