Question

The average annual expense E (in dollars) of a middle income family and the average annual amount T (in dollars) spent on telephone service during the period of 1992-2001 can be modeled by E= 1240x + 24,800 and T= 31x + 620 where x is the number of years since 1992. Write and simplify a model to show that the average annual amount spent on telephone services was 2.5% of the average annual expenses during the period.

Answer 1

What is x?

Answer 2

Please note that x is defined to be the number of years since 1992. We are to evaluate for the years 1992-2001. So...2001 is how many years after 1992?