Solubility?

Question

The formation constant for the bis(thiosulfato)argentate(I) ion is 2.0 x 10^13, while the solubility product constant for silver bromide is 5.0 x 10^–13. Considering the reaction,
AgBr(s) + 2 S2O3 2–(aq) Ag(S2O3)2 3–(aq) + Br–(aq)
What is the solubility, in moles per liter, of silver bromide in 0.200 molar sodium thiosulfate solution?

Answer 1

AgBr(s) + 2 S2O3 2–(aq) ->Ag(S2O3)2 3–(aq) + Br–(aq)

K = 2x10^-13 x 5x10^-13 = 10

y/(.2-y) = sqrt(10)

solve for y