A 50.00 mL solution of 0.3050 M AgNO3. was added to a solution of AsO43-. Ag3AsO4 precipitated and was filtered off. Fe3 was added and the solution was titrated with 0.2500 M KSCN. After 35.80 mL of KSCN solution had been added, the solution turned red. What mass of AsO43- was in the original solution?