How many moles of acidified FeSO₄ can be completely oxidised by one mole of KMnO₄

$\mathrm{KMnO}4 + {\mathrm{FeSO}}_4 + {\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{Fe}}_2{\left({\mathrm{SO}}_4\right)}_3 + \mathrm{MnS}{0}_4 + {\mathrm{K}}_2{\mathrm{SO}}_4 {\mathrm{H}}_2\mathrm{O}$ 

n - factor for KMnO₄ = 5 (MnO₄^- $\to$ Mn⁺²)

n - factor for FeSO4 = 1 (Fe⁺² $\to$ Fe⁺³)

criss-cross method

1mole KMnO₄ oxidizes 5 moles of FeSO₄