We have modelled the Ni-like and Co-like resonance lines emitted from Ni-like Silver X-ray laser media using a collisional radiative code. The code calculates intensities of Ni-like 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^{10}$$\longrightarrow$ 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^9nl$, Co-like 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^9$$\longrightarrow$ 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^8nl$ resonance lines emitted from silver. Intensities of photons emitted between Ni-like 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^9$$n^\prime l^\prime$$\longrightarrow$ 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^9$nl and Co-like 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^8$$n^\prime l^\prime$$\longrightarrow$ 1s$^2$2s$^2$2p$^6$3s$^2$3p$^6$3d$^8nl$ excited levels are also calculated. The optimum electron temperature and density for $J=0-1$ lasing at 13.9 nm is evaluated. The ratios of Co-like 3d–4p to Ni-like 3d–4p resonance lines are calculated with the aim that such ratios can serve as a diagnostic to measure electron temperatures.