Solve this:
An organic compound contains oxygen, carbon, hydrogen and sulphur.
A sample Of it with a mass Of 1.045 g Was burned in oxygen to give gaseous CO₂, H₂O, SO₂
These gases passed through 500.0 mL of an acidified 0.0200M KMnO₄ Solution, which caused the SO₂, to be oxidized to SO₄ ^{2 - ​}. Only part of the available KMnO₄ was reduced to Mn^{2 +}. Next. 50.00 mL of 0.0300 M SnCl₂ was added to a 50.00 mL portion of this solution. which still contained unreduced KMnO₄  
There was more than enough added SnCl₂  to cause all of the remaining MnO₄ ^- in the 50 mL portion to be reduced to Mn^{2 +}. The excess Sn^{2 +} that remained after the reaction was then titrated with 0.0100M  KMnO₄, requiring 27.28 mL Of the KMnO₄, solution to reach the end point. What was the percentage of sulfur in the original sample of the organic compound that had been burned?