= 17.1*(1-1/2.4)*0.6 = 17.1*(0.6 -1/ 4)
= 17.1*1.9
=17.1(2-0.1)
=34.2-1.71
=32.49答案不对呀！= 17.1*(1-1/2.4)*0.6 = 17.1*(0.6 -1/ 4) = 17.1*0.35 = 17.1*0.7/2= 11.97/2=5.985