bonjour
1/ 100-(45+9+4)=42%
2/ a/ 45/100 * 15.5/100 = (45*15.5)/(100*100)=0.07=7%
b/ 45/100 * (100-15.5)/100 = (45*84.5)/(100*100)=0.38=38%
3/ a/ 9/100 * 11.1/100=0.001=0.1%
b/ 9/100 * (100-11.1)/100=0.08=8%
4/ a/ 4/100 * 25/100= 0.01=1%
b/ 4/100 * (100-25)/100=0.03=3%