Test exercises in interviews

Was checking out other employers.

One (agency) asked me to perfom an unpaid exercise 4h under observation.

The one i signed (inhouse) gave me a task told me can you do that in the next few days will take 2/3 h

The page i they gave me the task to rank on the first position ranked a place lower than a category page of the same website.

I wrote that cat page x rank higher so you could set it noindex for fulfilling the task.

The interviewer told me later that he did that to sort out people.

How you handle exercises i decided for me i will not do anything over 3 h Also did you guys encounter trick questions in tasks if so which?