Find the Emf for the cell
Cr(gr) | Sn4+(aq, .059 M), Sn2+ (aq, .059 M) || Fe3+ (aq, .15 M), Fe2+ (aq, .015 M) | Pt(s) if the standard cell emf is .77 V at the cathode and .15 V at the anode. Answer in Units of V. If would be nice if you could show me step by step.