The molecular formula of a non-stoichiometric tin oxide containing Sn (II) and Sn (IV) ions is ${\mathrm{Sn}}_{4.44}{\mathrm{O}}_8$.
Therefore, the molar ratio of Sn (II) to Sn (IV) is approximately

In 1 mol of the given substance the number of moles of Sn (II) =  x moles and number of moles of Sn (IV) = y moles.

$\therefore$ x + y = 4.44 and 2x + 4y = 16

By solving x = 0.88 and y = 3.56

$\therefore$ mole ratio of Sn (II) to Sn (IV) is 0.247:1 $\cong$ I :4