Răspuns:
Explicație pas cu pas:
Fie a,b,c cele 3 numere, iar a+b+c este suma lor.
(a,b,c) proportionale cu (25%·(a+b+c); 20%·(a+b+c); 15%·(a+b+c)), deci
a/25%=b/20%=c/15%=(a+b+c)/(25%+20%+15%)=100%/60%=5/3=k, coeficientul de proportionalitate
atunci a=25%·(5/3)=(25/100)·(5/3)=(1/4)·(5/3)=5/12.
b=20%·(5/3)=(20/100)·(5/3)=(1/5)·(5/3)=1/3.
c=15%·(5/3)=(15/100)·(5/3)=(3/20)·(5/3)=1/4.
Deci, a reprezinta 5/12 din suma, b reprezinta 1/3 din suma, c reprezinta 1/4 din suma,
Verificare: 5/12+ 1/3 + 1/4 = 5/12 + 4/12 + 3/12 = (5+4+3)/12=12/12=1. corect.