Question

Consider a solution of CaCl2 and Mg(NO3)2 in which the concentrations of both Mg2+ and Ca2+ are the same, 0.01. M. Is it possible to separate Ca2+ from Mg2+ by selective precipitation of Mg(OH)2? To be precise, is it possible to precipitate 99.99% of magnesium without precipitating any calcium as hydroxides? For the sake of simplicity, assume that the precipitation reactions do not result in any change of the volume of the reaction mixture. The Ksp values of the calcium and magnesium hydroxides are 6.5 x 10-5 and 7.1 x 10-12, respectively.

I don't have access to my textbook right now (im on mobile) so I cant do much work on this. Please help, I'm SO lost.