Peanut butter monopolist Calvé supplies peanut butter to Albert Heijn in an isolated village. The supermarket is a monopolist in the village. Demand for peanut butter is given by:

Where denotes the price a consumer pays for peanut butter. The supermarket's costs have of marginal selling costs equivalent to 40 per unit plus the costs it pays Calvé for the peanut butter. Assume Calvé's marginal costs are equal to 12 and that its fixed costs are equal to zero.

a) Assume Calvé sells the peanut butter for a price of per unit to the supermarket. How much peanut butter will Albert Heijn offer to the market as a function of?