Robinson has a labor endowment of 80 units of labor and a utility function u(x.y) = min { 2x. 5y ]. The production of good x is x = 2(L )05 and for y it is y = 4(L,)05. For Robinson, the optimal amount of good x to produce is _units. 17.5 O 15.5 O 12.1 O 10,1