I keep getting the wrong answer for chemistry homework. Please Help

A 100.0 ml solution containing aqueous HCl and HBr was titrated with 0.1200 M NaOH. The volume of base required to neutralize the acid was 47.26 ml. Aqueous AgNO3 was then added to precipitate the Cl- and Br- ions as AgCl and AgBr . The mass of the silver halides obtained was 0.9983 .

What is the molarity of the HBr in the original solution?
What is the molarity of the HCl in the original solution?

HBr and HCl are both monoprotic and react in the same ratio (1:1) with NaOH

HBr NaOH ---> NaBr + H2O
HCl NaOH ---> NaCl + H2O

So the moles of NaOH used will be the same as total moles of HBr + HCl in the mixture

moles NaOH = molarity x litres
= 0.1200 M x 0.04726 L
= 0.0056712 mol

Therefore moles HCl + moles HBr = 0.00561712 mol

There is one Cl- ion in each HCl and one Br- ion in HBr
Therefore total moles Br- + Cl-