Bunuel
A park contains at most five of seven kinds of trees - firs, laurels, maples, oaks, pines, spruces, and yews - consistent with the following conditions:
If maples are in the park, yews are not.
If firs are in the park, pines are not.
If yews are not in the park, then either laurels or oaks, but not both are in the park.
If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces.
Which one of the following could be true?
(A) Neither firs nor laurels are in the park.
(B) Neither laurels, oaks, nor yews are in the park.
(C) Neither laurels nor spruces are in the park.
(D) Neither maples nor yews are in the park.
(E) Neither oaks nor spruces are in the park.
We have to look for the option which is possible. This means that as per given data the other 4 should not be possible.
(A) Neither firs nor laurels are in the park.Given: If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces.
This means that if even one of L and O is missing, then F and S both are present.
So if L is missing, then F must be present. So it is not possible that both F and L are missing.
(B) Neither laurels, oaks, nor yews are in the park.Given: If yews are not in the park, then either laurels or oaks, but not both are in the park.
If Y is missing, then L or O must be present. So it is not possible that all Y, L and O are missing.
(C) Neither laurels nor spruces are in the park.Given: If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces.
This means that if even one of L and O is missing, then F and S both are present.
So if L is missing, then S must be present. So it is not possible that both S and L are missing.
(D) Neither maples nor yews are in the park.Given: If maples are in the park, yews are not.
M and Y cannot be both together in the park but both of them can be absent from the park. No where are we given that if M is not in the park, then Y must be present. Hence this is possible.
(E) Neither oaks nor spruces are in the park.Given: If it is not the case that the park contains both laurels and oaks, then it contains firs and spruces.
This means that if even one of L and O is missing, then F and S both are present.
So if O is missing, then S must be present. So it is not possible that both S and O are missing.
Answer (D)It is important to understand negation operators and conditionals to solve this.
Conditionals discussed here:
https://youtu.be/MmlwcTlHZz8https://youtu.be/BW8Ijrhjjq8https://youtu.be/yQYkL1DSslA