Bradford T. answered 12/05/20
Retired Engineer / Upper level math instructor
a) let y =0.000025 for now for easier typing
Revenue is price time quantity
R(x) = xp = 72xe-yx
To maximize, take the derivative and set that to zero and solve for x.
R '(x) = 72(e-yx-xye-yx) = 72e-yx(1-yx)
1-yx = 0 --> x = 1/y = $40000
b) R(40000) = 40000(72e-y/y) = 72(4000)/e = $1059493