Answer:
$720
Explanation:
Given the following functions
Cost function C(x)=50x+400
Revenue function R(x)=80x-0.05x^2
P(x)=R(x)−C(x).
Profit function P(x) = 80x-0.05x^2 - (50x+400)
P(x) = 80x-0.05x^2 - 50x - 400
Substitute x = 40
P(40) = 80(40)-0.05(40)^2 - 50(40) - 400
P(40) = 3200-80-2000-400
P(40) =3200-2480
P(40) = 720
Hence the amount of profit made is $720