Maria won this year’s local sailboat race by beating Sue, the winner

OFFICIAL EXPLANATION

The structure of the argument is:

Premise: Maria won this year’s local sailboat race by beating Sue, the winner in each of the four previous years.
Conclusion: We can conclude from this that Maria trained hard. A quick glance at the argument reveals a gap between the premise and conclusion—winning does not necessarily guarantee that Maria trained hard. This is the connection we will need to focus on when considering the answer choices.

To further abstract this relationship, we can portray the argument as follows:

Premise: Maria won (which we could also call “A”)
Conclusion: Maria trained hard (which we could also call “B”). The answer that will justify this relationship is: A B. Which is the same as: Maria won Maria trained hard. A quick glance at the answer choices reveals that answer choice (C) matches this relationship (remember, “only if” introduces a necessary condition). Thus, the structure in this problem matches the first of the two examples discussed on the previous page. A large number of Justify questions follow this same model, and you should be prepared to encounter this form.

Answer choice (A): This answer does not justify the conclusion that Maria trained hard. The answer does justify the conclusion that Maria trained, but because this is not the same as the conclusion of the argument, this answer is incorrect. Another way of attacking this answer is to use the Justify Formula. Consider the combination of the following two elements: Premise: Maria won this year’s local sailboat race by beating Sue, the winner in each of the four previous years.

Answer choice (A): Sue did not train as hard as Maria trained. Does the combination of the two elements lead to the conclusion that Maria trained hard? No, and therefore the answer is wrong.

Answer choice (B): This is a Mistaken Reversal of what is needed (and therefore the Mistaken Reversal of answer choice (C)). Adding this answer to the premise does not result in the conclusion. In Justify questions featuring conditionality, always be ready to identify and avoid Mistaken Reversals and Mistaken Negations of the relationship needed to justify the conclusion.

Answer choice (C): This is the correct answer. Adding this answer to the premise automatically yields the conclusion.

Answer choice (D): Because we do not know anything about Sue except that she lost, this answer does not help prove the conclusion. If you are having difficulty understanding why this answer is incorrect, use the Justify Formula. Consider the combination of the following two elements: Premise: Maria won this year’s local sailboat race by beating Sue, the winner in each of the four previous years.

Answer choice (C): If Sue trained hard, she would win the sailboat race. The combination of the two creates the contrapositive conclusion that Sue did not train hard. But, the fact that Sue did not train hard does not tell us anything about whether Maria trained hard.

Answer choice (E): Because this answer addresses only the relative speed of the two racers, it fails to help prove that Maria trained hard.

C it is .
Use of word "only if" .
If there are more reasons other than hard training when Maria can beat sue then we cannot conclude that training hard is the only reason for Maria's win

Agree with C.

If X happens than Y will happen;

here it only works in one direction.

therefore, if Y happens, than X did not necessary happen too.

Answer C.

not thAn, thEn dear

Otherwise, C as well. This is the conditional clause that validates the conclusion without a doubt.

Okay ! so the contention of doubt is between B and C.
Before that, always remember that winning does not necessarily mean that the person has worked hard, may be the competitor gave up or was not prepared.

B: "if" .. This is a mistaken reversal of what is needed. We know this, but does it necessarily mean that she worked hard? If leads us to a probabilistic situation
C: Adding this choice to premise takes us to the conclusion.

For anyone wondering, this is actually an LSAT JUSTIFY question, and NOT an assumption question. The OA is correct, but it is worth pointing out in case there is any confusion moving forward

Conclusion: Because Maria trained hard, she could beat Sue, who was champion for 4 years.

Assumption: If Maria did not train hard, she couldn't beat Sue in the race.

(A) Sue did not train as hard as Maria trained. - Negating this statement does not break conclusion.

(B) If Maria trained hard, she would win the sailboat race. - Cannot tell about this based on given premise.

(C) Maria could beat a four-time winner only if she trained hard. - Yes, clearly the assumption.

(D) If Sue trained hard, she would win the sailboat race. - Cannot comment on Sue from given Premise.

(E) Sue is usually a faster sailboat racer than Maria. - We cannot comment who is fast from the given premise.

Option C is correct. But how do I eliminate option B.

Negation of B
If Maria didn't train hard, she would win the sailboat race.
So this breaks the conclusion that Maria trained hard.

Please clarify my doubt.

anairamitch1804 has done a nice job explaining (B) vs (C) in this post. Let us know if you have any further questions!

I didn't understand clearly, say if there was an option choice which stated Maria trained hard, so she will win the race would this be the right answer. how do I use negation technique to eliminate between B and C?

Thank You

Maria won this year’s local sailboat race by beating Sue, the winner in each of the four previous years. We can conclude from this that Maria trained hard.

The conclusion follows logically if which one of the following is assumed?

(A) Sue did not train as hard as Maria trained.

(B) If Maria trained hard, she would win the sailboat race.

(C) Maria could beat a four-time winner only if she trained hard.

(D) If Sue trained hard, she would win the sailboat race.

(E) Sue is usually a faster sailboat racer than Maria.

It was B and C that confused me just like anyone. But I found C relatively better than B. C left no scope of error in judgement. In B, I found that even if Maria trained hard, it is possible that during a slight error might have costed her the race or may be Sue got little lucky. So there are many number of possibilities that can exist still.

In C, two things just slashed the requirement - beating a four-time winner and only if.

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