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