The ionisation eq for MNCO3 is given by
MnCO3 --> Mn^2+ + CO3^2-
Recall Ksp=[Mn^2+][CO3^2-]
From the chemical reaction one moles of manganese and carbon reacts
Here molar solubility of MnCO3 is 4.2 * 10^-6 M;
Which means that when 4.2 * 10^-6 moles of [Mn^2+] reacts, it also reacts with 4.2 x 10^-6 M of CO3
Thus Ksp= 4.2 x 10^(-6) x 4.2 x 10^(-6) = 17.64 * 10^(-6+(-6)) = 17.64 * 10^(-12)
