NaNo_3 dissolved in NaCl saturated solution

[LANS]

Homework Statement

Explain why sodium chloride will precipitate from a saturated aqueous solution when sodium nitrate is dissolved in this solution.

Homework Equations

no equations.

The Attempt at a Solution

The saturated NaCl solution cannot dissolve any more sodium, so as NaNo3 dissolves sodium must precipitate. It reacts with chlorine to precipitate as NaCl.
Why does it do this?

Any help would be appreciated.

 

[chemisttree]

Think about the solubility product...

 

[LANS]

I figured it out.thanks. I'd write it here but I've already handed in the assignment.