41.2X8.1+11X1.25+53.7X1.9=41.2*(10-1.9)+1.1*12.5+53.7*1.9=412-41.2*1.9+1.1*12.5+53.7*1.9=412+1.9(53.7-41.2)+1.1*12.5=412+1.9*12.5+1.1*12.5=412+12.5*(1.9+1.1)=412+12.5*3=412+37.5=449.5