Answer:
what price will maximize the country's revenue
maximizing price, therefore, is 90+x, and the number of barrels sold is 7,000,000−100,000x.
Explanation:
revenue=price×quantity
The price is 90+x, where x is the change in price, and the quantity is 7,000,000−100,000x
take the derivative of that function.
r(x)=(90+x)(7,000,000−100,000x)=−100,000x2−2,000,000x+630,000,000⇒r′(x)=−200,000x−2,000,000
maximizing price, therefore, is 90+x, and the number of barrels sold is 7,000,000−100,000x.