We know that if life ever existed on the Moon, there would be signs of

Question

We know that if life ever existed on the Moon, there would be signs of life there. But numerous excursions to the Moon have failed to provide us with any sign of life. So there has never been life on the Moon.

The pattern of reasoning in the argument above is most similar to that in which one of the following?

(A) We know that the spy is a traitor. We do not know that the general is a traitor. So the general is not a spy.
(B) If we have any mayonnaise, it would be in the refrigerator. But the refrigerator is almost empty. So it is unlikely that we have mayonnaise.
(C) Hendricks will win the election only if voters are concerned primarily with fighting crime. Hendricks is in favor of tougher criminal penalties. So voters will probably go with Hendricks.
(D) If rodents are responsible for the lost grain from last year's harvest, we would find signs of rodents in the warehouses. And we have found signs of rodents there. So rodents are responsible for the lost grain.
(E) If their army is planning an attack, there would either be troop movements along the border or a transfer of weapons. But intelligence reports show no indication of either. So their army is not planning an attack.

Rishi2502 · Answer

could anyone tell me y choice D can't be the answer?

MJS1997 · Answer

D is not an answer because the question asked for which of the following is similar to the above reasoning.

In the question:
If life existed ( A ) --> there would be signs of it ( B )
As no signs have been found ( ~B ) --> there is no life ( ~A )

In the case of D:
If rodents responsible ( A ) --> there would be signs of it ( B )
As signs have been found ( B ) --> rodents are responsible for lost grain ( A )

This is not similar to the reasoning in the question. Hence, we can eliminate option 'D'

vatsagrawal · Answer

Existence of life = B
Sign of life = A

Statement 1: B can only be true if A is true.
Statement 2: A is not true, so, B is not true.

Answer options:
(A) 
Spy is Traitor
General status is unknown.
Hence, general is not a traitor.

This is not parallel to the question stem as there is no dependency between being a general and a spy, while, for life to be present, there must be signs of life.

(B) this option can be ignored as the conclusion is not certain. It mentions an "unlikeliness"

(C) Similar to (B), there is no certainity.

(D) (i felt this one had a trap with the word "sign" it) I did not exclude this option completely right off the bat, but rather went for (E) as it was a better fit.

(E) "If their army is planning an attack, there would either be troop movements along the border or a transfer of weapons. But intelligence reports show no indication of either. So their army is not planning an attack."

Planning of attack = B
Movement of troops / transfer of weapons = A

Part 1 mentions that if the army plans an attack, there would be a movement of troops / weapons, i.e. B can only be true after A is true.
Part 2 mentions that A is not true, and so B is not true.

This is inline with the reasoning in our answer stem and hence, the right choice.

unraveled · Answer

We know that if life ever existed on the Moon, there would be signs of life there. But numerous excursions to the Moon have failed to provide us with any sign of life. So there has never been life on the Moon.

The pattern of reasoning in the argument above is most similar to that in which one of the following?

Life existed on Moon (A) ----> sign of life (B)
Many excursions ----> No sign of life (~B) ----> Life never existed on moon (~A).

(A) We know that the spy is a traitor. We do not know that the general is a traitor. So the general is not a spy. - WRONG. 
spy (A) ----> traitor (B)
General  ????  (C)
General (C) --/--> spy (A)
Missing middle part.

(B) If we have any mayonnaise, it would be in the refrigerator. But the refrigerator is almost empty. So it is unlikely that we have mayonnaise. - WRONG.
Mayonnaise (A) ----> Refrigerator (B)
Refrigerator (B) ---->  almost  empty (C) ----> Possibly no mayonnaise (~A)
It goes nowhere.

(C) Hendricks will win the election only if voters are concerned primarily with fighting crime. Hendricks is in favor of tougher criminal penalties. So voters will probably go with Hendricks. - WRONG.
Voters concerned with fighting crimes (A) ----> Hendricks'll win election (B)
Hendricks favours tougher criminal penalties (C) ----> Voters choose Hendricks(A)
Additional input/logic is there.

(D) If rodents are responsible for the lost grain from last year's harvest, we would find signs of rodents in the warehouses. And we have found signs of rodents there. So rodents are responsible for the lost grain. - WRONG.
Rodents responsible for lost last year's harvest grains (A) ----> sign of rodents in warehouse (B).
Sign of rodents in warehouse (B) ----> Rodents responsible for lost grain (A).
Reverse in not applied. Straightforward logic.

(E) If their army is planning an attack, there would either be troop movements along the border or a transfer of weapons. But intelligence reports show no indication of either. So their army is not planning an attack. - CORRECT.
Army planning attack (A) ----> troop movements/transfer of weapons (B).
No troop movements/transfer of weapons (~B) ----> Army planning no attack (~A).
Exact match.

Answer E.

D3N0 · Answer

https://gmatclub.com/forum/we-know-that ... l#p3497205 Same Question

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