g1[x_]=0.02 (1-x/100);
g2[x_]=0.3 (1-x/100);
g3[x_]=0.8 (1-x/100);
h[x_]=x/(1+x^2);
abb=Plot[{g1[x],g2[x],g3[x],h[x]},{x,0,105},PlotPoints->100,ImageSize->{400,300}];