Please help with homework!?

a 563-mg sample containing only CaCO3 (100.1 mg/mmol) and SrCO3 (147.6 mg/mmol) is dissolved in an acid; Na2C2O4 is added to precipitate CaC2O4 (128.1 mg/mmol) and SrC2O4 (175.6 mg/mmol). The oxalate precipitate is filtered and dried to yield 703 mg of the anhydrous mixed oxalates. Calculate the percentages of CaCO3 and SrCO3 in the mixture. Show ALL your work!!