I don't understand. Please help!

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?

There were 25 students who answered to a survey about sports. four-fifths of them like football. how many students like football?

Each day jake donates money to the global.