Stim ca c=(a+b):3 dar a=2×b+15
=> c=(2×b+15+b):3=(3×b+15):3
C=3(b+5):3=b+5
Ne ducem in relatia a+b+c=2768 si inlocuim a si c in functie de b
=> 2×b+15+b+b+5=2768
=> 4×b+20=2768=> 4×b=2768-20=>4×b=2748 => b=687
Mergem in a si inlocuim b-ul
=> a=2×b+15=2×687+15=1389
c=b+5=1389+5=1394