IMO most solving such questions are more of a guess than having a good logic behind them, unless they are obvious. Something that seems logical to the test composer may not seem to be logical to you. Classic example is how lawyers argue about a particular situation and interpret it so differently.
I many times get baffled by the explanation given for CR questions. The explanation argues that the most logical answer is the right option, but there is atleast another option which is equally probable on the same line of reasoning.
Sometimes the difference between two options is so subtle that the amount of time to spend on the questions seems insufficient.
Just my 0.02c.