A 30 mL solution is known to contain some amount of lead(ii) nitrate, Pb(NO3)2. 3 mL of 0.1 m NaF was added to this solution, forming a precipitate. After filtration and dehydration, the precipitate is found to have a mass of 117 mg. What is the concentration of Pb(NO3)2 in the original solution? You may assume that all activity coefficients are equal to 1, and that the solution is aqueous and dilute.