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

1.  If your total earnings up to week 5 are 69.74403 dollars, and your total earnings up to week 15 are 83.74403 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 an automobile is at milepost 238.1353 after having traveled for 5 hours and at milepost 287.1353 after having traveled for 11 hours, then what is its average speed? Why do we say average speed rather than just speed?

3.  If the water in a uniform cylinder has depth 152.6003 cm at clock time 5 seconds and depth 183.6003 cm at clock time 11 seconds, then at what average rate is the depth changing? What we say average rate rather than just rate?

4.  If you are earning money at an average rate of 13 dollars per week, and if at the end of week 8 your total earnings are 98.00967 dollars, then what will be your total earnings that the end of week 18?

5.  If an automobile is traveling at the rate of 66 mph, and is at milepost 591.9361 after having traveled for 9 hours, then what milepost would be after having traveled for 15 hours?

6.  If the depth of water in a uniform cylinder is changing at an average rate of 12 cm/second between clock times 10 s and 15 s, and if its depth at clock time 10 seconds is 93.40317 cm, then what is its depth at clock time 15 seconds?

7.  If your total earnings up to week 4 are 50.33863 dollars, and if you earn money at a constant rate of 13 dollars per week, then at what week will your total earnings be 63.33863 dollars?

8.  If an automobile is traveling at the rate of 68 mph, and is at milepost 393.9231 after having traveled for 6 hours, then after how many hours of travel will it have reached milepost 12?