All work must be complete and legible to get full credit. Your final answer$($s$)$ must be clearly shown by putting a circle$/$rectangle around it$.$ ALL work must be done on a separate sheet of paper. Use this sheet as a cover sheet. You may use the calculate function in your calculator to give the answers to each.

The Silver Surf Company manufactures surfboards has a fixed cost of $$300$ per day and a marginal cost of $$240$ per day.

a$.$ Assume the cost per day is a linear function defined as a function of $x,$ number of surfboards produced each day. Write an equation for the cost function.

b$.$ Write an equation for the average cost function.

c$.$ As production increases $(x$ gets really large$),$ what is the average cost approaching? $(*$hint: set the window on your calculator so $x-$max is $500).$ Draw a picture of your friendly window.