87. Solving a chemistry problem

28. One way to determine the temperature of liquid nitrogen (or another liquid at low temperatures) is as follows: a piece of tin (m = 0.2 kg) is placed in liquid nitrogen and temperature equilibrium is allowed to set in. The tin is then removed and placed in a mercury tube (m = 2 kg) at 90 C. When the tin and mercury come to equilibrium, the temperature becomes equal to 53.2 C. The heat capacity of tin is 205 J/kg*K. Find the temperature of liquid nitrogen.