Using the stoichiometry, the approach is to start with what you know (an amount of stuff) and solve for an amount:
50 ml Iron soln (1 liter/1000ml)(.532 moles Fe(II)/liter)(1 PM/3Fe(II))(1 liter/ .825 mole PM)(1000 ml/liter) = ans in ml of PM sol'n (PM stands for permanganate)
Note that you can ignore the ml-->l and back steps when you do calculation.