the dollar price for a barrel of oil sold at a certain oil refinery tends to follow the demand equation below where x is the number of barrels of oils on the hand in ( millions ) a) how much should be charged for a barrel of oil if there are 6 million

It would help if you proofread your questions before you posted them.

What equation?

The dollar price for a barrel of oil sold at a certain oil refinery tends to follow the demand equation​ below, where xx is the number of barrels of oil on hand​ (in millions).

​a) How much should be charged for a barrel of oil if there are 66 million barrels on ​ hand?
​b) What quantity xx will maximize​ revenue?
​c) What price should be charged in order to maximize​ revenue?
ppequals=negative one fifth x plus 160−
1
5x+160

To answer the question, you'll need the specific demand equation for the oil refinery. Unfortunately, you haven't provided the demand equation in your question. However, I can explain to you how you can calculate the price if you have the demand equation.

The general form of a demand equation is as follows:
P = a - b*x

Where:
P = Price of a barrel of oil
x = Number of barrels of oil on hand (in millions)
a, b = Constants representing the demand factors

If you have the demand equation, you can substitute x = 6 million into the equation to determine the price. Simply replace x with 6 and solve for P.

For example, if the demand equation is P = 10 - 0.5x, you would substitute x = 6 into the equation:

P = 10 - 0.5 * 6
P = 10 - 3
P = 7

Therefore, the price for a barrel of oil, with 6 million barrels on hand, would be $7, based on this example demand equation.

So, to determine the price in your specific case, you would need to provide the demand equation for the oil refinery.