solid state

1. if the ratio of the coordination number of P to Q is Y:Z then the formula of the solid containing atoms of P and Q is...........???

2. the lattice energy of solid NaCl is 180kcal/mol. the dissolution of solid in water in the form of ions is endothermic to the extent of 1 kcal/mol. if the solution energies of Na+ and Cl- are in 6:5 ratio, what is the enthalpy of hydration of Na+ion....????

P.S : help me with the step-by-step approach to such problems..........