.A perfectly competitive constant cost industry contains a number of firms, each of which has the following long-run total cost function, where q is annual output:

TC = 0.01q³- 1.2q²+ 101q

The market demand curve for the product is:

Q = 7,000 - 20p

where Q is annual industry sales.

(a)Calculate the long-run equilibrium output of the industry.

(b)How many firms are there in the industry in long run?