Smirnov, on whose dependency after the death of his par

Smirnov, on whose dependency after the death of his parents there were two young sisters, sold Fedorov a three-room apartment, which had been transferred to him by inheritance from his father. The deal was made at the initiative of Fedorov, who knew about the difficult financial situation of Smirnov and his sisters. With the money from the sale, Smirnov and the sisters purchased a two-room apartment.
After a year and a half, Smirnov found out that the apartment he sold was estimated at the market at that period well above the amount paid by Fedorov. Smirnov filed a lawsuit in court to declare the transaction null and void, motivating his claim that Fedorov took advantage of the difficult financial situation of Smirnov and his sisters. At the court hearing it turned out that Fedorov was aware of the prices for apartments, as he headed one of the real estate agencies. Solve the case.