[0.75×42.7－0.573×25＋57.3]÷3×760
=[0.75×42.7－57.3×0.25＋57.3]÷3×760
=[0.75×42.7+57.3×0.75]÷3×760
=[0.75×(42.7+57.3)]÷3×760
=75÷3×760
=25×4×190
=100×190
=19000