Conditional Sequencing Diagramming Drill #6

[OBA1207]

Hi PowerScore team,

I'm working my way through the pure sequencing section of your book, and having some trouble with page 385, Drill #6. It reads:

6. M is scheduled earlier than Q, or scheduled later than T, but not both.

I don't quite follow why both the Q and T are in each of the two diagrams.

If I want to diagram

M > Q
- - -
T

Why is that not just M > Q? How do we know that the T must be placed somewhere later than the M here swell?

The fact that says 'but not both' really confuses me, and Q>M>T or T>Q>M would make a lot more sense to me. I know this is explained on page 380-381, but I'm not following.

If you have any further clarification, that would be greatly appreciated!!

Thanks!

[Steve Stein]

Hi Oba,

That's a great question—it's interesting that those three words ("but not both") can make a rule so much more challenging!

Let’s start with a slightly simpler example of the same idea:

• Either A will attend or B will attend, but not both.

This one sentence actually relays two rules:

1) Either A or B will attend—one of these two things must happen.

2) Those two things cannot both happen: A and B cannot both attend. In other words:

• If A is there, B cannot go: A B
  
  ...and if B is there, A cannot go: B A

Now, let’s see how this relates to your more complex sequencing example from the Logic Games Bible:

• M is scheduled earlier than Q, or later than T, but not both.

Again, this single sentence really relays two rules:

1) M is either earlier than Q or later than T—one of these two things must happen.

2) Those two things cannot both happen. M cannot be both earlier than Q and later than T. In other words:

• If M is earlier than Q, M cannot be later than T (so in that scenario, M must be earlier than T):
  
  M > Q M > T In this scenario, M is scheduled earlier than both Q and T.
  
  
  ...and if, on the other hand, M is later than T, M cannot be earlier than Q (so in that scenario, M must be later than Q):
  
  T > M Q > M In this scenario, M is scheduled later than both Q and T.

So, the rule that you asked about dictates that M must either be earlier than both Q and T (from the first scenario directly above), or later than both Q and T (from the second scenario).

I hope that's helpful! Many students find this type of rule challenging, so please let me know whether this is clear—thanks!

~Steve


(For more practice with these concepts, check out the PowerScore Logic Games Bible Workbook, which is comprised of complete logic games, expansive step-by-step explanations, and a wide variety of practice drills—including one that is entirely focused on these types of potentially confusing conditional sequencing questions)

[OBA1207]

Steve, this makes it so much more clear now! Thank you so much, and I look forward to asking more questions in the near future on here

O