When they invest K dollars, a fishery can produce Q(K) pounds of fish per month, where Q(K)=107K1/3. In t months from now, their total investment will be K(t)=0.5t2+300t+510 dollars: At what rate is the production of fish changing with respect to time 6 months from now? In 6 months from now, the fisher's production will be at a rate of