How to solve complex Carnot engine efficiency numerical for Karachi Board XII Physics?

Hi everyone! I am a second-year pre-engineering student from Karachi preparing for my upcoming BIEK intermediate board exams. I am really struggling with the numerical problems in Chapter 11 (Thermodynamics), specifically calculating the efficiency of a Carnot engine when multiple temperature shifts are given in the question. I have tried using the standard formula \(\eta = 1 - \frac{T_C}{T_H}\) after converting Celsius to Kelvin, but I keep getting confused on multi-stage problems found in Karachi past papers. Could any teacher or senior guide me on how to break down these specific multi-stage board questions step-by-step? Any shortcut tips for the exam would be highly appreciated. Thanks!