JEE Advanced 2018 Chemistry question

To measure the quantity of dissolved in an aqueous solution, it was completely converted to using the reaction, (equation not balanced). Few drops of concentrated HCl were added to this solution and gently warmed. Further, oxalic acid (225 mg) was added in portions till the colour of the permanganate ion disappeared. The quantity of (in mg) present in the initial solution is . (Atomic weights in g mol: Mn = 55, Cl = 35.5)