I'm confused if a divisor is a number u use to divide a number and do long divsion or 10 divides by 20 equals 2

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?

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?

Will give a: 122 b: 90 c: 48 d: 180