Exercise 29* For the following pairs of variables, write out what the doubling
property would say about the situation, and use that to decide if the two quantities
are proportional. State clearly any assumption you need to make.
a. The distance I drive per year and my annual car insurance bill.
b. The distance I drive per year and the total amount I pay for gas in one
year.
c. The amount of time you study and the score you get on the test.