123. Solving a chemistry problem

1. Calculate the weight of a sample containing about 60% MnO2, so that after interaction with 50.0 ml of 0.05215 M H2C2O4 solution, the excess acid would be titrated with 25 ml of KMnO4 solution (1.00 ml of KMnO4 solution is equivalent to 1.035 H2C2O4 solution).