00:01
So given this demand function, we're trying to find the price or less sophisticated demand, given this particular x value.
00:06
So to do that, we have to do p over x divided by p prime.
00:11
That would be equivalent to 800 minus 4x over x divided by negative 4.
00:23
So when we plug in 150, we get 800 minus 4 times 150 over 150 divided by negative 4.
00:36
So simplifying this here, we get that we have 200 over negative 600, and so, which is equivalent to negative 2 over 6, which equals negative 1 3rd.
00:52
So that is the answer to the first part.
00:57
Then if we get to the second part here, so it's asking us to maximize revenue.
01:01
First, we have to find what the revenue function is, which is x times the demand function, which is 800 x minus 4x squared.
01:09
So from here, let's go ahead and take the derivative of this.
01:15
So that's equal to 800 minus 8x.
01:20
And we're now going to set this equal to 0...