=K10*0.25+MAX(K10-25000,0)*0.05+MAX(K10-50000,0)*0.05+MAX(K10-100000,0)*0.05
=if(k10<=25000,k10*25%,if(k10<=50000,k10*30%,if(k10<=100000,k10*35%,k10*40%)))