Chemistry question! i need help!?

35.6 mL of 0.5000 M AgNO3 is added to 270.0 mL of water which contains 5.832 g K2CrO4. A red precipitate of Ag2CrO4 forms. What is the concentration, in mol/L, of unprecipitated CrO42-? ume that Ag2CrO4 is completely insoluble.