The graph shows the number of cellular phone subscribers in

The graph shows the number of cellular phone subscribers (in millions) in a State from 2005 to 2008. 2005 2006 2007 2008 200 220 240 260 280 x y (2005,206.3) (2008,270.8) x y graph (a) Use the given ordered pairs to find the slope of the line. (b) Interpret the slope in the context of this problem. (a) The slope of the line is nothing. (Type an integer or a decimal.) (b) Interpret the slope in the context of this problem. Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. The number of subscribers increased by an average of nothing million each year from 2005 to 2008. (Type an integer or a decimal.) B. The number of subscribers decreased by an average of nothing million each year from 2005 to 2008. (Type an integer or a decimal.)

Solution

It seems that we have to find the slope for these two ordered pairs:

(2005,206.3) (2008,270.8)

Slope = (270.8 -206.3)/( 2008 -2005) = 64.5/3 = 21.5 million per year

The number of subscribers21.5 million increased by an average of nothing million each year from 2005 to 2008