Bill heats his house with natural gas. The gas usage is measured in therms (T). In January of 2007 he used 125 therms over 34 days (D) and the average temperature (T) was 49 degrees farenheit. This year in January he used 190 therms over 31 days and the average temperature was 43 degrees. He wants to know if the added usage was because of the lower average temperature or if he was being wasteful. How would you calculate the answer to that question? Can you develop an equation to normalize the usage for temperature and number of days?
Linear equations are applied to energy usage. The solution is detailed and well presented. The response received a rating of "5/5" from the student who originally posted the question.