P(x) = 0.005x³ + 0.02x² + 30xDifferentiating w.r.t to x we get,P'(x) = 3(0.005)x² + 2(0.02)x + 30P'(3) = 3 × 0.005(3)² + 2(0.02)(3) + 30P'(3) = 0.135 + 0.12 + 30P'(3) = 30.255