To be honest, everyone working in science, engineering, data science, actuarial science, or really any numbers-heavy field should be able to answer that first question by reasoning through it. It may be slow, it may require drudging up some distant memories from college, or it may even require a visit to Wikipedia; but if you work with numbers and you can't do that example problem, you owe it to your profession to brush up on your statistics. People not understanding pretty basic statistics like that is a major root cause of almost all the problems in science today (p-hacking, etc.). Many, many statistics problems (including the example) can be solved easily (again: not necessarily quickly) by the basic technique of scribbling out a rectangle or tree of possibilities and the probability of each.
As a math Ph.D. dropout who took the first two exams: the trouble is that you have to solve them quite quickly. The tests weren't too hard for me, but I did have to practice the sorts of problems I would see so that I didn't have to spend too much time thinking. Even then, I didn't walk in feeling like it was a slam dunk.
