Answer:
A) Quantity, q = 5 units.
B) Revenue, r = $75.
Explanation:
The demand function for a product is

where p is the price in dollars when q units are demanded.
Revenue = Price × Quantity
Using the given information, the revenue function is


.... (1)
Differentiate with respect to q.


Equate
to find the critical value of q.


Divide both sides by q.

The value of q is 5.
Differentiate
with respect to q.

So, the revenue function is maximum at q=5.
Substitute q=5 in equation (1).
Therefore, the level of production that maximizes the total revenue is 5 units and the revenue is $75.