The average cost of manufacturing a quantity q of a good, is defined to be

a(q) = C(q)/q.
The average cost per item to produce q items is given by
a(q) = 0.01q2 − 0.6q + 13, for q >0.

(a) What is the total cost, C(q),of producing q goods?

For this do I just put the given equation over q and then get rid of a q from the numerator to not have a denominator?

What is the minimum marginal cost?

What is the practical interpretation of this result?
The marginal cost is at a minimum when the (blank)per item is $ (blank)

I'm assuming that the first blank is total cost and that the second blank is the answer to part a?

(c) At what production level is the average cost a minimum? What is the lowest average cost?

Compute the marginal cost at
q = 30.

I'm so sorry for all the questions. I'm really having trouble understanding this topic.