Question

Suma a 3 numere este 505. Daca se adauga primului 1/7 din el, al doilea 1/9 din el si al treilea 3/9 din el, devin egale. Aflati numerele.

Answer 1

a+b+c=505
a+a/7=b+b/9=c+3c/9
8a/7=10b/9=12c/9=k
8a=7k; 10b=9k; 12c=9k
a=7k/8;  b=9k/10 ; c=9k/12
 a+b+c=505

7k/8+9k/10+9k/12=505  aducem la acelasi numitor comun (120)
15*7k+12*9k+90k=505*120
105k+108k+90k=60600
k=60600:303
k=200
a=7k/8=7*200/8=
a=175
b=9k/10=9*200/10=1800/10=180
b=180
c=9k/12=9*200/12=
c=150

Verificare
a+b+c=175+180+150=505
505=505