Let's see a calculation for a case that reaches equilibrium.
Basis: 100 Kg sand and 2 Kg salt
Neglect the volume and density changes due to the salt.
This is not a realistic calculation if you
select a small value of the adhering water because only very coarse
gravel would hold so little. We know from building
sand castles on the beach that 100 Kg of sand could have
100 Kg or more of adhering water.
What you should learn:
When there is much adhering liquid, it is
difficult to get a high yield.