Sample problems redox and electrochemical reactions

Question: The half-reaction for the reduction of MnO₄⁻ to Mn²⁺ in acidic solution is MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O. What mass of MnO₄⁻ can be reduced by 1