It is necessary to insulate an IC, with three different plastic materials, which have different thermal conductivity that are k3=3,k2=1 and k1=0.2, all with British units and that go from outside to inside respectively; the established temperatures are T327C and Tamb=24C. An economic investigation yields the following information: Cost (mmp)=(9.3) (insulation thickness) 24 y Cost (mmp)=1/3+1.5/3 (total thickness) y Cost useful energy =$1/cal. Calculate the thickness for each layer and to avoid heat loss to the outside. Make your calculations by the economic thickness method