Complete Question Explanation
Must Be True. The correct answer choice is (E)
This Must Be True question’s stimulus contains three distinct, and fairly straightforward, statements given as fact, where each describes the relationship between two conditions. This type of logical presentation is commonly known as Conditional Reasoning, and will be discussed in detail later in the course; for now, simply follow the connections that exist between the three premises. You should also recognize the strength of the language used in this stimulus, particularly compared to some other Must be True questions that you have encountered. Remember that strong, absolute language in the stimulus allows you to draw conclusions that are more definite than those following from stimuli with more generalized wording.
The first sentence makes the strongly worded claim that everyone sitting in the athletic office’s waiting room that morning at 9 AM had registered for a beginners tennis clinic. The next sentence tells us that John, Mary, and Theresa were all sitting the waiting room at 9 AM. At this point we can make an inference about John, Mary, and Theresa: all three must have registered for a beginners tennis clinic (since they were in the waiting room and everyone in the waiting room registered). Finally, in the last sentence, we are told that no accomplished tennis player would ever register for a beginners tennis clinic. Thus another inference is possible: since John, Mary, and Theresa did all register for a beginners tennis clinic, it follows that John, Mary, and Theresa are all not accomplished tennis players. Since this inference was the more difficult of the two to formulate, it seems likely that the correct answer would follow from it.
Note too the extent of what can (and what cannot) be properly concluded from this stimulus. While we can make some inferences about John, Mary, and Theresa (registered for the beginners clinic, not accomplished tennis players), it is tempting to assume more than can be known. For instance, while we know that John, Mary, and Theresa were in the athletic office’s waiting room at 9 AM, can we know with certainty that they were the only people there? Or that no one else registered for a beginners tennis clinic? The answer to both of these questions is, “No. We cannot know that with absolute certainty.” So be sure to ask yourself whether the answer choice that you select is in fact fully supported/proven by the stimulus when doing Must be True questions.
Answer choice (A): While you can conclude that none of the people sitting in the school’s athletic office at 9 AM are accomplished, that does not necessarily mean that they have never played tennis. It is entirely possible that one could have played tennis at some point and still not be an accomplished tennis player.
Answer choice (B): Words like “only” should catch your eye on the LSAT, as they are extremely limiting to the idea being presented. For this answer, can you reasonably conclude that it must be true that no one in the office at 9 AM registered for anything except a beginners tennis clinic? Hopefully it is clear that while they certainly did register for a beginners tennis clinic, they could have also registered for any number of other things as well.
Answer choice (C): You know that John, Mary, and Theresa registered for a beginners tennis clinic, but you cannot know that they were the only people to do so. Certainly others could have registered for that clinic too.
Answer choice (D): Again, you know that John, Mary, and Theresa were sitting in the athletic office at 9 AM, but you do not know that no one else was sitting there with them. Thus you cannot state with certainty that they were the only people there.
Answer choice (E): This is the correct answer choice. As discussed above, the final inference to be drawn from this stimulus is that John, Mary, and Theresa are not accomplished tennis players. The test makers attempt to introduce some confusion here by only mentioning John and Theresa, but the truth of the inference still applies even if all three are not specifically referenced.