At a certain factory, output is given by Q = 60K^1/3L^2/3 units, where K is the capital investment (in thousands of dollars) and L is the size of the labor force, measured in worker-hours. If output is kept constant, at what rate is capital investment changing at a time when K = 8, L = 1,000, and L is increasing at the rate of 25 worker-hours per week?