The derivative of
in the direction of a vector
is

With
, we get

and
,

Then

Answer:
The maximum revenue is 16000 dollars (at p = 40)
Step-by-step explanation:
One way to find the maximum value is derivatives. The first derivative is used to find where the slope of function will be zero.
Given function is:

Taking derivative wrt p

Now putting R'(p) = 0

As p is is positive and the second derivative is -20, the function will have maximum value at p = 40
Putting p=40 in function

The maximum revenue is 16000 dollars (at p = 40)
Answer:
500
Step-by-step explanation:
D. 100/135 the rest of them equal 135%