Cable Subscribers On the basis of data recorded between 2001 and 2007, the number of...

Cable Subscribers On the basis of data recorded between 2001 and 2007, the number of cable subscribers in the United States as a function of the average monthly basic cable rate can be modeled as

s(r) = 89.391 - 6.486 ln r million subscribers

when the average basic rate is r dollars per month. (Source: Based on data from National Cable & Telecommunications Association)

a. Use the model to estimate the number of subscribers (in millions) for the following monthly basic rates: $34, $38, $42.

b. Interchange the input/output values for the three points found in part a. Use the three inverted points to find an inverse function r with input s.