Solve the all parts of given problem:
Problem: A student calibrates a constant volume gas thermometer in dry ice (-78.5°C) and in boiling ethyl alcohol (+78.0°C). He records pressures of 0.900 atm and 1.635 atm respectively.
Part A: What value (in °C) does he obtain for absolute zero?
Part B: What pressures would he record at the ice point (0°C) and steam point (100°C)?
I need tutor help to solve the above problem and hint: Use P = A + BT, where A and B are constants.