All firms in a competitive industry have long run total costs of C(q) = 20 + 4q + q2

1.a.(5 points) Determine the level of output at which average cost is at its minimum. Determine marginal cost and average cost at this level of output.  

1.b.(5 points) If there is free entry and exit from this industry, what will be the long run competitive price and how much will our representative firm sell?