### different demand functions that have the same cost function

I need to know how to calculate demand and price for two different demand functions that have the same cost function. P1 = 20 - .0125Q1 P2 = 40 - .025Q2 ATC = MC = 3.00. How do I calculate the price and quantity for each? How does ATC/MC factor into the price/quantity estimate? What is the economic profit for each?