41.2*8.1+11*1.25+53.7*1.9
=41.2*(10-1.9)+11*1.25+53.7*1.9
=41.2*10-41.2*1.9+53.7*1.9+11*1.25
=412+12.5*1.9+1.1*12.5
=412+12.5*(1.9+1.1)
=412+12.5*3
=412+37.5
=449.5