80. A weighed amount of magnetite containing 72.36% iron, equal to 1.00 g, is dissolved in acid. To what volume should the resulting solution be diluted so that 17.00 cm3 of KMnO4 with C (1/5 KMnO4) = 0.1525 mol / dm3 is spent on titration of iron ions contained in 50 cm3 of this solution?