The anwser is 17 idk what she did but that’s wrong
For this case, we can model the problem as a triangle with a right angle.
Where,
x, y: lengths of the sides of the triangle
d: hypotenuse of the triangle
We then have the following relationship:

Clearing d we have:
Answer:
A functions that would best model the situation above is:
D square root
Answer:
The maximum revenue is $900, obtained with 30 people
Step-by-step explanation:
Naturally, the answer should be a number equal or higher than 20, because up to 20 persons, each one pays the same. Lets define a revenue function for x greater than or equal to 20.
f(x) = x*(40-(x-20)) = -x²+60x
Note that f multiplies the number of persons by how much would they pay (here, assuming that there are more than 20).
f is quadratic with negative main coefficient and its maximum value will be reached at the vertex.
The value of the x coordinate of the vertex is -b/2a = -60/-2 = 30
for x = 30, f(x) = 30*(40-(30-20))=30*30=900
So the maximum revenue is $900.
The answer should be I think b