math
posted by Ashton .
The demand function for a certain brand of CD is given by the following equation where p is the wholesale unit price in dollars and x is the quantity demanded each week, measured in units of a thousand.
P=0.01X^20.1X+6
Determine the consumers' surplus if the wholesale market price is set at $4/disc. (Round your answer to two decimal places.)
$ ?

Did you provide the all information? Because all you can do with the given information is to plug P=4 into the equation and find x, but x is quantity of CD demanded.
Consumer surplus is the difference between the max price a consumer willing to pay and the actual price they do pay.
So you do have the actual price they pay  $4, and you can find how many thousand of CDs is being sold, but you need to have (I believe) extra information, such as price consumers willing to pay.