[(5/8-0.625)*1000+3.6*25/9]/25/8
=[(0.625-0.625)*1000+3.6*25/9]/25/8
=[0*1000+3.6*25/9]/25/8
=[3.6*25/9]/25/8
=0.4*25/25/8
=0.4/8
=0.1/2
=0.05