p=peri
m=meri
c=caisi
p=3+1/2din m
m=1/3din c
c=?
p+m+c=84
3+1/2 din 1/3din c+1/3din c +c=84
3+1/6 din c+1/3din c +c=84
3+c ori (1/6 +1/3+1)=84 dupa ce calculezi paranteza iti da: 3+c ori 3/2=84
c ori 3/2=84-3
c ori 3/2=81
c=81:3/2
c=54
m=1/3din 54=18
p=3+1/2din 18
p=12
....sper ca te.a ajutat....