(1)3/4解侍腔:设去年买入价逗吵为a,今年买入价为山谈侍b,定价为cc*85%-a=c*25%c*75%-b=c*30%a=0.6cb=0.45cb/a=3/4(2)3.224解:成本c=0.15*6.5+0.2*2.2+0.6=2.015售价为xx-c=60%cx=1.6c=1.6*2.015=3.224(3)52%现价为a,降价前为bb*65%*80%=aa/b=52%