We're given that QD = 500 - 10P, where:

• QD represents the quantity demanded of a good.
• P represents the price of that good.

Using the following formula, let's perform a few calculations:

TR = QD * P

TR = 500P - 10P2

We can take the derivative of the TR function in order get the price at which the total revenue is maximized:

It is given by:

dTR / dP = 0

500 - 20P = 0

Or, 500 = 20P

Or, 500 / 20 = P

Or, 25 = P

Thus, P = 25

Hence, the required price where the total revenue is maximized is given by: P = $25.