Solve the following by describing a picture, and by constructing a graph:

1.  If your total earnings up to week 7 are 98.73873 dollars, and your total earnings up to week 12 are 113.7387 dollars, then what are your average earnings per week? Why do we say average earnings per week rather than just earnings per week?

2.  If you are earning money at an average rate of 9 dollars per week, and if at the end of week 8 your total earnings are 70.43631 dollars, then what will be your total earnings that the end of week 14?

3.  If your total earnings up to week 7 are 48.54274 dollars, and if you earn money at a constant rate of 7 dollars per week, then at what week will your total earnings be 55.54274 dollars?

4.  If an automobile is at milepost 580.3036 after having traveled for 8 hours and at milepost 653.3036 after having traveled for 17 hours, then what is its average speed? Why do we say average speed rather than just speed?

5.  If an automobile is traveling at the rate of 37 mph, and is at milepost 323.3186 after having traveled for 9 hours, then what milepost would be after having traveled for 15 hours?

6.  If an automobile is traveling at the rate of 69 mph, and is at milepost 537.8707 after having traveled for 8 hours, then after how many hours of travel will it have reached milepost 17?

7.  If the water in a uniform cylinder has depth 129.9148 cm at clock time 6 seconds and depth 153.9148 cm at clock time 16 seconds, then at what average rate is the depth changing? What we say average rate rather than just rate?

8.  If the depth of water in a uniform cylinder is changing at an average rate of 16 cm/second between clock times 7 s and 15 s, and if its depth at clock time 7 seconds is 108.3893 cm, then what is its depth at clock time 15 seconds?