Which sequence isn’t a geometric progression?

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

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?

Benefit(s) from large economies of scale, in which the costs of goods decrease as output increases. natural monopolles perfect competition