Question

Aflati numerele rationale pozitive x,y,z,stiind ca aritmetica a oricaror doua dintre ele este egala cu 30

Answer 1

x+y/2=30=> x+y=60
y+z/2=30=> y+z=60=> y=60-z
x+z/2=30=> x+z=60=> x=60-z

60-z+(60-z)=60
60-z+60-z=60
120-2z=60
60=2z
z=30

x=60-30=> x=30
y=60-30=> y=30