Petty much., but it's used more to describe your own condition rather than another person. E.g "I've worked 15 hours today, I'm complete whacked"

In New Zealand, whacked is an informal way to say very tired or exhausted.

It's saying that you are expected to work on the case independently but to check in with the manager when you start writing and a few times during writing to make sure you are on working on the same assumptions as your manager.

The first is correct and the third would only be correct if you were asking specifically about a set of books, similar to"when did you eat the last cookie?" but it's not a common usage

As above but also

Some Sentences with New Words

1) I ran out of fruits - bananas and apples, which I always prefer to have in a certain amount.
2) She has always been unmarried, so she devoted her life to others.
3) He starts gambling as soon as he gains some money.
4) An ancient prophecy tells that the city will disappear one day.
5) The scale of losses during that war was unprecedented.
6) You can preach indefinitely, it means nothing to me.
7) Severity of local life makes people patient and hard-working.