If Tiger Toys faces a demand curve of P=85 .25Q and a MC=ATC=20, then the output would be?

If Tiger Toys faces a demand curve of P=85 .25Q and a MC=ATC=20, then the output would be?
65 units
85 units
130 units
32.5 units

For the perfectly or purely competitive firm, profit maximization occurs at an output level where?
P=MC
MC=ATC
P=AVC
p

Using the linear approximation system to estimate the profit maximizing price requires that the managers know the costs of production and ?
the production function
one price and quantity of demand
two prices and quantities of demand
decision making process of the marketplace