Let C(w) be the shipping cost (in dollars) for a package that weighs w kilograms, where
C(w)={8w+5,6w+45,0≤w≤20,20<w≤50.
The average cost per kilogram is A(w)=wC(w) for 0<w≤50. Determine the weight w (in kilograms) that minimizes A(w) on this domain.