Seems like the obvious (if dishonest) thing would be to use a throwaway phone # to get the test, then spend a day or so solving it, then type it in (with plausible delays) using your real number a day later. Assuming the test is roughly the same each time (even if details are different, it's probably of the same general class).

In grading, the results of 6-8h of work entered in 2h would look more impressive than 3h of work in 3h, I suspect.

(Sometimes I hate that whenever someone gives me a situation, my first thought is "how can this be cheated or gamed", followed by "what controls can I put in place to prevent that, and and what costs"; it's basically automatic.)