How to approach lengthy looking questions?

Question

@Arjun sir ,@Bikram sir, Other Veterans

Please guide me on how to approach such questions which need calculation of each times seperately and then finding a conclusion.

for eg.

1. https://gateoverflow.in/8492/gate2015-3-34
2. https://gateoverflow.in/1992/gate2014-2-33

While writing test I fear wasting time to find results for all, and I believe there can be a option-elimination like approach to do this??