From the statement of the problem we know that:
• the demand function is:

where p is the price in dollars when q units are demanded,
• the revenue function for the product is:

We must find the level of production q that maximizes the total revenue R.
We maximize the function R(q), by equalling to zero its first derivative:

The level of production that maximizes the total revenue is q = 10 units.
The maximum value of the revenue is:

Answer
• q = 10 units,
,
• R = $1000.