> Implicit in the design of most tests is the idea that a person's ability to quickly solve moderately difficult problems implies a proportional ability to solve very difficult problems if given more time. This is clearly jumping to a conclusion. I doubt there is any credible evidence to support this.

I think this approach is effectively testing if a student studied the material. It makes the correlation between memorization and understanding. Recall a piece of information is fast if avaliable.

Its a commonly expressed experience among university students that learning memorization techniques and focusing on solving previous exams is a disproportionately effectively way to pass courses.

It's technically more impressive to pass the exam by never doing a single similar problem before and deriving a solving method or forumla that wasn't memorised.

I took deliberate effort to avoid looking at previous exam question for a course until the week before, since it cased good grades at little value to me long term.