Notatii:
s = numarul de barne de stejar
b = numarul de barne de brad
1 t = 1000 kg
b + s = 300
28b = 46s +1000
*-*
b + s = 300 | x 46
28b – 46s =1000
*-*
46b + 46s = 13800
28b – 46s =1000
*------------------- adunam ecuatiile
74b / = 14800
b = 14800 / 74 = 200 barne de brad
s = 300 – 200 = 100 barne de brad