An editor is compiling a textbook containing essays by several differe

Question

An editor is compiling a textbook containing essays by several different authors. The book will contain essays by Lind, Knight, or Jones, but it will not contain essays by all three. If the textbook contains an essay by Knight, then it will also contain an essay by Jones.

If the statements above are true, which one of the following must be true?

If the statements above are true, which one of the following must be true?

(A) If the textbook contains an essay by Lind, then it will not contain an essay by Knight.
(B) The textbook will contain an essay by only one of Lind, Knight, and Jones.
(C) The textbook will not contain an essay by Knight.
(D) If the textbook contains an essay by Lind, then it will also contain an essay by Jones.
(E) The textbook will contain an essay by Lind.

Tracy95 · Answer

If the textbook contains an essay by Knight, then it will also contain an essay by Jones. 
Translated into: have Knight MUST have Jones 
=> have Knight MUST NOT have Lind (because the textbook will not contain essays by all three). Lind & Knight cannot co-exist. 
So A is correct.

D is not correct because it is just one possibility. We can have a textbook containing essays by Lind but not containing any essay by Jones.

(I welcome any feedback on my thoughts)

Posted from my mobile device

TheNightKing · Answer

Book wont have all 3. L/K/J
If K --->J

That means if I include K then J will be included. But I won't have all 3 together.

Based on responses:

(A) If the textbook contains an essay by Lind, then it will not contain an essay by Knight.
 So If I pick L, I can't pick K. Why? Because if I have L and I pick K I will have to include J. That means I will have all 3. So this must be true.

(D) If the textbook contains an essay by Lind, then it will also contain an essay by Jones.
If I pick L then I may or may not pick J. There is no relation defined here. I can only include L and live happily. So this is not true.

PTD1995 · Answer

Regarding your explanation of answer D): TheNightKing

An editor is compiling a textbook containing essays by several different authors.. Hence, we should have at least 2 authors. Don't you think?

It seems to me that both answers A and D) are not incorrect.

Give kudos, if you agree

TheNightKing · Answer

PTD1995

I don't quite agree. Yes You can say that there will be at least 2 authors but then we are give three authors in total. For example : So if A is selected then B is not selected then C can still be selected and that makes 2 authors.

Makes sense?

If you are still not convinced then solve this question and provide explanation of each option. May be that will help

mavrck0102 · Answer

I picked A, but i cant see a reason why D is wrong. Can anyone please help?

AndrewN · Answer

When I see no Expert Reply in the thread, I sometimes feel compelled to share my thoughts. A  must be true  question is self-explanatory, but you have to be careful not to take an idea and run with it—assumptions are not your friend.

It may prove easiest to start with the final line of the passage, which we can shorten to  if K, then J , or K → J.   The book  cannot  contain essays by  each  of L, K, and J

There is no need to include anything on the first line of the passage because we cannot interpret  several different authors  as only those mentioned in the second line. There could any number of other authors  not  named Lind, Knight, or Jones. (Remember what I said above about making assumptions.)

We can now approach the answer choices.

In short,  if L,  not  K . This  must be true  because it combines the two crucial pieces of information above. If K were to also feature in the book, then K → J tells us that all three of L, K, and J would have essays in the book, violating the second bullet point. Most of the time, I advocate looking at all the answer choices in a CR set, but in a must-be-true format, as soon as you have an answer that you cannot argue against, you may be better off selecting that answer and moving on. Other options might only create uncertainty, and absolute conditions call for definitive solutions.

Quite clearly, K and J may appear together, so this one is out.

Why not? We can copy and paste the same analysis from the previous answer choice and apply it here.

Maybe, maybe not. There is no L → J conditional statement in the passage, so L could appear alone from the three authors or L and J could both have essays in the book. Nothing prohibits either scenario.

There are a few possibilities here:

1) L alone
2) L and J
3) K and J
4) J alone

That is it. Remember, the passage tells us that the book  will contain essays by Lind, Knight, or Jones, but it will not contain essays by all three , so there cannot be any more than two of these authors together, and K cannot feature alone, since K → J is a given condition. Only half of the valid possibilities include an essay by L, so this answer choice is incorrect.

Perhaps the question makes more sense now. Good luck with your studies, everyone.

- Andrew

VerbalBot · Answer

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An editor is compiling a textbook containing essays by several differe

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