LG Game 3 Question 13 Explanation, by LSATHacks
This is a general could be true question. It gives you no indication what to look for. This sort of question often takes longer to solve, as you have to try each choice. Fortunately, there are a couple of tricks you can try:
- Looking through the answers to determine which seems easiest to do within the rules (pick one that obeys a rule).
- Choose the hardest rule and use it to eliminate answers.
I’ll first use the most restrictive rule, and then explain what I mean by “obeys a rule”. The most restrictive rule was this diagram combining rules 1 and 3:
S must be before M and V. S can’t be first, and S needs at least two open spaces after it for M and V.
This eliminates C, D and E!
- C: Places M before S
- D: Places V before S
- E: Places S fourth….and T fifth. There’s no space for M and V after S!
That’s convenient! This “most restricted factor” trick shows up in all types of logic games game and will eliminate many answers for you.
Next, what do I mean by obeys a rule? Let’s look at A and B:
- A: T before V….that isn’t mentioned in any rules.
- B: S before V. That helps comply with rule 3!
So B is making things easy for us by checking one item off the list of rules we have to obey. This doesn’t make B correct, of course….but it means it is a more promising place to start.
So we only really have to consider A and B, and B is the most likely answer. Now, if you’re using the scenarios (from the main diagram section), you’ll see that none of the scenarios allow for T to be directly before L. So, A is wrong and B must be CORRECT.
If you hadn’t found the scenarios, you could use this method to disprove A. It places T and L second and third:
Next, consider rule 4: we need to have V – T – H, or H – T – V.
We can’t put V in slot 1, because we need to put V after S. So we have to put H first.
But that places H before L. And rule 2 says that if H is before L, then M must be before L. Which isn’t the case here (there’s no open space before L), so this diagram violates the rules.
So B must be CORRECT, by process of elimination. Here’s scenario 3 from the setup, which proves that this works:
If you didn’t have the scenarios, you’d just have to sketch S second, V third, and fill in the rest of the spots while obeying the rules.
- M goes after S
- T – H need to go after V, since there’s no space to put them before it.
- That leaves L to go first
Note that when constructing scenarios like this you want to think in terms of rule blocks, not isolated variables.
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