Skip to Main Content

PrepTest 78, Game 4, Question 23


This is the last question of Pt 78 game number four. And here we have a rule substitution question we are looking for which answer would be a perfect replacement for the condition that W must be earlier than the two recorded auditions. So we want to pretend like this rule is not here. Rule number three and we're looking for an answer that will do exactly what this rule did and no more.

That means the correct answer has to follow these two criteria. First, the correct answer at a minimum, it must be something that had to be true under the original rules. And that's because if an answer choice is saying something that was not true under the original rules of the game, then it would be changing an aspect of the game. If you tried to replace rule number three with an answer choice that is different from what had to be true under the original rules, then you would now be limiting the game more than this third rule originally limited the game.

So the first criteria is the answer choice must be true under the original rules. The second criteria for the correct answer, and the correct answer has to be both of these criteria. The second is that the answer choice, if true, has to be something that would force the W to go before K and L. If one of these answers does not actually make you put the W before K and L, then it's not actually doing what rule number three did.

So let's take a look at the answer choices. A says Z is the only letter, the only addition that can go earlier than W. So first was that true under the original rules, that Z was the only letter that could go before W? And if you were doing enough work on the other questions you probably realize that that was something that had to be true.

And this is because the only other letter that looks like it could go before W is this Y. But then the problem is, if you put W in 3, Y in 2, Z in 1, this isn't gonna work because then, the last three letters have to be K, L and T, the fourth spot is not recorded. And so T is the only one that could fit in the fourth spot right now, but then you don't have room for the K to go before the T.

So it turns out that the W could never go in the third spot. W is either gonna go in 1 or 2. And that's why if you put the W and two, the only letter that could go before it is the Z So that's why A passes the first criteria. Z is, in fact, under the original rules, the only audition that could go earlier than W.

It doesn't have to go earlier than W. But it's the only one that could go earlier than W. And now let's see the impact of answer choice A, if Z is the only one that can be earlier than W. And that is actually putting every other letter after W. So that saying, wherever you put the W, you cannot put any other letter besides Z, before W.

That automatically means that K will come after the W and the L will also come after the W, as well as the Y and the T. So this is why answer choice A actually does provide a perfect substitute. Under the original rules, z was the only letter that could go earlier than W. And if A were true, it would mean that K and L have to go after w just like the rule we're trying to replace.

Let's take a look at why the other answers are wrong, B says W has to go immediately before or after Z, but the problem with this one is this answer is not forcing K and L to come after W. If you took what B said, and you put it in the spot of the third rule, then you could put K in first, and then you could z2, w3 you could make L go in 5, you could put a Y in 4 and then a T in 6.

And this order is something that's possible under answer choice B. But this is putting the K before W, so it's not doing what we want the rule to do. Answer choice C says W has to be before L. And again, this is something that is not going to force W to go before K. You could still put K in 1, you can put Z in 2, W in 3, you can put the L in 5, Y in 4, T in 6.

This is something consistent with what answer choice C says, but it's not doing what the old rule did which is put the W before both K and L. The next answer D is probably the most popular answer choice here. W must be either 1 or 2. Now the problem with this answer is like B and C. It doesn't actually force you to put K and L after W.

Under answer choice D this is theoretically something that is possible. You could put W in 2, you could put an L in 1, you can put Z and Y in 3, 4, make spot five a K and then put T and since this follows what answer choice D says and it's consistent with all the other rules. But it's not forcing us to follow rule number three, or rather, the effective rule number three It's not forcing us to put w before L and K.

So that's why answer choice D is not a perfect substitute. And finally, he says the first spot cannot be recorded, but that's not gonna do anything because even if it's true that the first spot cannot be recorded, you could just put a Z in 1, you could put an L in 2, W in 3 and you'll notice here we are coming up with an order that follows what answer choice E says. The first spot is now recorded but it doesn't actually force the old relationship, E does not force us to put W before K and L, so E is not a perfect substitute.

Read full transcript