 For this problem, we need to calculate HDD for one full week. The data that is given is each day what is the outside temperature, average outside temperature. For example, Sunday, the average outside temperature is 49 degrees Fahrenheit. Monday, 47 degrees Fahrenheit. Tuesday, it's 51. And Wednesday, it is 60 degrees Fahrenheit. And on Thursday, it is 65. Friday, 67. And on Saturday, it is 58. So we need to calculate heat and degree days for each day. One day, that is Sunday, the outside temperature is 65 minus 49, the outside temperature will give you the degree days. Similarly, 65 minus 47 degrees Fahrenheit, one day times 65 minus 51, in this case, one day times 65 minus 60, and one day 65 minus 65. This will be 0. One day, 65 minus 67. Remember, when it exceeds 65, the heating degree days would be 0. In this case, also it is 0. One day on Saturday, it is 65 minus 58. In this case, it is 7. These two are 0s. This is 5. And this is 14. And this happens to be 18. And here, it is 16. So the total sum is, for one full week, it is 60 degree days. This is equal to 60 degree days.