=IF(A2>75,A2*15%,IF(A2>55,A2*20%,IF(A2>45,A2*25%,IF(A2>25,A2*30%,IF(A2>15,A2*60%,IF(A2>10,A2*90%,IF(A2>5,A2*120%,IF(A2>1,A2*150%,A2*350%))))))))+A2

Try the above