Air is to be compressed from 3 bar and 303K to pressure of 15 bar in a multistage compression process with inter-stage cooling reducing the temperature down to 30 °C. The system allows maximum compression ratio of three (3) that should not be exceeded. a) Calculate number of compression stages required and the compression ratio b) Determine the actual power required by the first (1st) compressor [3] [10] c) Determine the actual power required by the last compressor and the outlet temperature [12] Assume Cp of air to be that of Nitrogen = 32 - 5.5 × 10-3 T + 2. 5 × 10-5 T 2 . For Air, Tc = -140.74 °C and Pc = 37.25 bar. Assume the polytropic efficiency of 75% for each compressor.