A company manufacturing surfboards has fixed costs of $300 per day and total costs of $5,100 per day for a daily output of 20 boards.

1. Assuming that the total cost per day ?(?) is linearly related to the total output per day ?, write equation for the cost function.
2. The average cost per board for an output of ? boards is given by ?(?)/?. Find the average cost function.
3. Sketch a graph of the average cost function, including any asymptotes, for 1?30.
4. What does the average cost per board tend to as production increases?