Abbottsville, a medium sized suburban community, has seen a steady increase in its population over the past 15 years. In 1995, the population was around 25,000. The population has increased at a rate of about 1,000 people per year since then. The graph below shows the trend described above. Use the graph to answer the following question:

If the trend continues as shown, what is the expected population of Abbottsville in 2015?

A
45,000

B
41,000

C
40,000

D
50,000

Step-by-step explanation:

Good thing we don't need the graph to answer this question.  We are going to solve it analytically instead of graphically!

Let's call 1995 year 0, and at year 0, the population was 25000.  The coordinate for this is (0, 25000).  If the population has increased at a rate of 1000 people per year, that is the slope of the line. (Normally, population growth is exponential.  But since our growth was given as an increase in people as a number as opposed to the increase in people as a percentage, this is linear.)

We will use the point-slope form of a line to write the model for this situation, then use the model to answer the question.

y - 25000 = 1000(x - 0) and

y = 1000x + 25000

Going back to the fact that 1995 is year 0, that makes 2015 year 20.  We will sub in a 20 for x to solve for y, the population expected in the year 2015:

y = 1000(20) + 25000 and

y = 20000 + 25000 so

y = 45000

Approximately 45000 people in the year 2015, choice A.