a1+a3+a5+...+a99=s1;a2+a4+...+a100=s2;s1+s2=s100=145,
s1=50*a1+50*(50-1)d,s2=50*a1+50*50*d;
100a1+50*49*0.5+50*50*0.5=145
a1=-23.3代入得s2=50*(25-23.3)=85