Trefore in t years the carbon monoxide level will be pt

Question

The carbon monoxide level in a city is predicted to be 0.02x^3/2 + 1 ppm (parts per million), where x is the population in thousands. In t years the population of the city is predicted to be x(t) = 12 + 2t thousand people. Therefore, in t years the carbon monoxide level will be P(t) = 0.02(12 + 2t)^3/2 + 1 ppm. Find P'(2), the rate at which carbon monoxide pollution will be increasing in 2 years.