a) x=(12,1-11,9):4+4,5 =0,2:4+4,5=0,05+4,5=4,55
y=[(2,3+1,5)*12,5]:(2,05-1,25)= 3,8*12,5:0,8=47,5:0,8=59,375
media aritmetica= (X+Y):2=(4,55+59,375):2=63,925:2=31,9625
b) x=[3,15+4,05)*36,9]:[(17,5-10,3)*0,41]=(7,2*36,9):(7,2*0,41)=265,68:2,952=90
y=21,7*(11,8-4,5)=21,7*7,3=158.41
media aritmetica=(x+y):2=(90+158,41):2=248,41:2=124,205
