X₂(g) + Y₂(g) ⇌ 2Z(g)
X₂(g) and Y₂(g) are added to a 1 L flask and it is found that the system attains the above equilibrium at T(K) with the number of moles of X₂(g) , Y₂(g) and Z(g) being 3, 3 and 9 mol respectively (equilibrium moles). Under this conditions of equilibrium, 10 mol of Z(g) is added to the flask and the temperature is maintained at T(K). Then the number of moles of Z(g) in the flask when the new equilibrium is established is ______. (Nearest integer).