Cost per mole
Table salt : Rs 0.878
Table sugar : Rs 23.63
<h3>Further explanation</h3>
Given
Cost table salt (NaCl) = 15/kg
Cost table sugar(sucrose-C12H22O11) = 69/kg
Required
cost per mole
Solution
mol of 1 kg Table salt(NaCl ,MW= 58.5 g/mol) :

mol of 1 kg Table sugar(C12H22O11 ,MW= 342 g/mol) :

Simple!
Atomic number= number of protons AND number of electrons (in an atom)
Mass number= number of neutrons