#1 - Global

[Administrator]

Complete Question Explanation

The correct answer choice is (A).

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

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E):

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

[brownac123]

Hello,

Confused to why A is the correct answer? Thanks.

[Adam Tyson]

I'll do my best to help explain that without a good picture of the diagram, brownac123!

First, we know that S is before O:

S O

And O is before R, V, and Z:

O R, V, Z (in your actual diagram you would want to draw three separate lines or "branches" from O to each of these other three variables)

Z is before L, so:

Z L

And finally, T is before both L and M:

T L, M

Now, combine these rules to make a more powerful set of inferences. I'll just deal with some of those links for the moment, combining the first rule with a portion of the second rule and then with the third rule, like so:

S O Z L

Already, L is being forced towards the later part of the overall order, since it must come somewhere after at least three variables (S, O, and Z).

But then bring in the last rule, which also puts T before L. Now L is even later in the order, with at least 4 things coming before it (S, O, Z, and T). That means that L can be no earlier than 5th! That's why A is the correct answer - L cannot be one of the first four kinds, because at least four other kinds must precede it.

Meanwhile, the others all COULD be in the first four:

M only has to be after T, so it would be possible to put T first and M second. Answer B is therefore out.

R is only required to be after O and S (S O R), so it could be as early as third, and therefore could be among the first four kinds. C is out.

V is in the same position as R - it only has to be after S and O, and could therefore be as early as third, just like R. That knocks out answer D.

And Z also only has to be after S and O, just like R and V, so it, too, could be as early as third. That gets rid of answer E.

Games like this are all about counting. How many things MUST be before such-and-such a variable? How many things MUST be after it? Those questions will help you determine how early and how late in a sequence a variable could be. For example, in this game, how many things MUST be after S? I count 5: O, R, V, Z, and L. That means that S can go no later than third out of eight. And how many MUST be before S? None! So S could be as early as 1st! (and since it can go as early as first and as late as third, we can also infer that it could also go second).

Try that with any one of these variables after drawing out all those connections, and you'll see which ones can be early, which can be towards the end, which ones are very flexible, and which ones are very limited. Then you'll be ready for anything they ask!