Each marble bag sold by lashonda's marble company contains 5 green marbles for every 3 red marbles. if a bag has 24 red marbles, how many green marbles does it contain?

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?