p(q) = 5280 - 13·q
E(q) = p(q)·q = 5280·q - 13·q^2
G(q) = E(q) - C(q) = 5280·q - 13·q^2 - (0.0116·q^3 - 2.4823·q^2 + 349·q + 4000) = - 0.0116·q^3 - 10.5177·q^2 + 4931·q - 4000
G'(q) = - 0.0348·q^2 - 21.0354·q + 4931 = 0 --> q = 180.5094527 ME
C(180.5094527) = 54343 GE