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

1.  If your total earnings up to week 8 are 87.74709 dollars, and your total earnings up to week 18 are 98.74709 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 14 dollars per week, and if at the end of week 7 your total earnings are 94.42023 dollars, then what will be your total earnings that the end of week 17?

3.  If your total earnings up to week 4 are 50.2979 dollars, and if you earn money at a constant rate of 13 dollars per week, then at what week will your total earnings be 63.2979 dollars?

4.  If an automobile is at milepost 544.1062 after having traveled for 8 hours and at milepost 614.1062 after having traveled for 18 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 51 mph, and is at milepost 248.7095 after having traveled for 5 hours, then what milepost would be after having traveled for 15 hours?

6.  If an automobile is traveling at the rate of 48 mph, and is at milepost 360.7224 after having traveled for 8 hours, then after how many hours of travel will it have reached milepost 18?

7.  If the water in a uniform cylinder has depth 103.7356 cm at clock time 8 seconds and depth 118.7356 cm at clock time 18 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 29 cm/second between clock times 9 s and 18 s, and if its depth at clock time 9 seconds is 253.8993 cm, then what is its depth at clock time 18 seconds?

9.  If the depth of water in a uniform cylinder is changing at an average rate of 18 cm/second as it depth changes from 119.3186 cm at clock time 7 seconds to 137.3186 cm at an unknown clock time, then what is the unknown clock time?