Can someone please help me with this problem. The following cell is set up to measure the concentration of K^+ in blood serum

Ag,AgCl | KCl(aq), c=1mol/L | K^+ selective membrane | KCl, c mol/L in serum || NaCl(aq), c=1mol/L | AgCl,Ag
1) If the cell potential difference is +0.148V and the temperatsure 25 degrees, use Nerst equation to calculate an estimate of the K^+ concentration in the serum
Any help would be greatly appreciated