#17 - Local

[Administrator]

Complete Question Explanation

The correct answer choice is (B).

Answer choice (A):

Answer choice (B): This is the correct answer choice.

Answer choice (C):

Answer choice (D):

Answer choice (E):

This explanation is still in progress. Please post any questions below!

[skimmmm]

What are the steps I need to take to make the inference that leads to the correct answer in this question? I got so far as to say that when Q is out, V also needs to be out, but it took me much longer to determine what other element needed to stay in in order to be able to fill all of the slots. After a few tries, I ended up choosing S as the one that needed to stay in, and sure enough, I was able to narrow down the answer choices to just two options. After that, it was clear that of the remaining options, only one of them was possible, since V was already out.

Is there another faster way to figure this out? I think I only got to the correct answer after running through multiple options, which was after I had completed blind review.

[Paul Popa]

Hi Skim,

Great question! I definitely understand the desire to get to the correct answer as quickly as possible. For games with a lot of conditional reasoning like this one, I would highly recommend writing the contrapositive of each rule in addition to the rule, as many answers can be deduced from a quick glance at the contrapositive. I would also recommend creating a mini-diagram for this question with Q out. As you saw, rule 2 leads to V being out as well, so we can quickly eliminate A and C.

From here I would check each answer choice, starting with B. I don't see any rule getting triggered that prevents R and S from being selected together, so we'll keep B for now.

I would eliminate D pretty quickly because of rule 3: if H is selected, I can't be.

That brings us to E. The contrapositive of rule 4 tells us that if I is selected, either G or S cannot be, or neither. This alone doesn't necessarily make E false, so let's quickly test it. If G and I are in, we would need to put S out, but if S is out, it would be out together with V, thus triggering the contrapositive of rule 5 forcing F out as well. However, there's only room for three paintings to be out, not four, so E can be eliminated.

So by process of elimination, B is the correct answer. In my experience with Must Be True questions in games, the incorrect answers are very rarely answers that could be true but don't have to be true--they're almost always answers that can never be true based on the rules given. Make sure to have each rule and its contrapositive diagrammed properly and check them as often as needed. By doing this, I was able to tick off three answer choices quickly, and testing the last one also led to a fast removal. Hope this helps!