In the United States, the annual consumption of cigarettes is declining.

Question

In the United States, the annual consumption of cigarettes is declining. The consumption c in billions of cigarettes per year since the year 2000 can be approximated by the formula c = -9.4t + 431 where t is the number of years after 2000. Use this formula to predict the years that the consumption of cigarettes will be less than 200 billion per year.

Answer 1

c = -9.4t + 431

c < 200

-9.4t + 431 < 200.

 

Solve this inequality by methods taught in Algebra course.

 

Hint: move the term involving t to opposite side of the inequality, where it will have a positive coefficient.

Then combine the constants on other side of inequality.  You then have 231 < 9.4t

Solve for t; t will be > some particular positive number of years (to be added to 2000 to give actual year).