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Please, I really need help with this!

I'm reviewing for an exam and ran across a question that has me rather stumped. I tried simply applying the Nernst equation but it seems I'm still missing something importantn "An electrically excitable cell with a resting potential of -70mV the following conditions are present (temperature is 37°C): Intracellulär Extracellular K+ 160nM 5mM Na+ 20nM 140mM Cl- 10nM 120mM Ca2+ 100mM 1mM 1. When the cell depolarisering [Ca2+] rises to 15uM, while the membrane potential reaches +61mV. Under these conditions , would Ca2+ move Into or out of the cell? 2. Which way would Na+ move? 3. Which way would K+ move if Na+ were allowed to dominate? The above is my translation! Let me know if something is unclear. Now, my problem is mainly question number 3, I honestly have no idea how to approac this. I've tried asking friends as well and the don't really understand how to answer that either. EDIT: Edited for clarity