a=k/2
b=2k/5
c=3k/8
k/2+2k/5+3k/8=51
aducem la acelasi numitor
20k+16k+15k=2040
51k=2040
k=2040/51
k=40
atunci rezulta ca
a=20
b=16
c=15
Verificare
20+16+15=51
exercitiul 3
daca b/y=2 => a/x=b/y=c/z=2 =>a=2x
b=2y
c= 2z
=> a+b+c=2x+2y+2z
=2(x+y+z)
=2*4,5
=9
