Some of these are poorly worded. Why does the answer to the May one keep talking about 30 seconds passing when the only time mentioned in the problem is 30 minutes? 30 seconds gives Nick at least 10 seconds per possible solution, he should have tried them all by then.

It should talk about the number of tries so far (one each), the length of time it took is irrelevant. But why are they even taking turns when they have separate padlocks and could easily brute-force it? I get the concept they're going for but the premise doesn't fit and just confuses things.