Given that Craig bought a treadmill for 400 dollars.
Useful life of the macine = x
Hence annual purchase cost spread over x years will be 400/x per year.
In addition, there is an annual maintenance cost of 36 dollars.
Hence Average annual cost in dollars = purchase cost per year+maintenance cost per year
= [tex]\frac{400}{x} +36 \\= \frac{400+36x}{x}[/tex]
Hence answer for rational function is
either [tex]\frac{400}{x} +36[tex]
Or [tex]\frac{400+36x}{x}[/tex]
