One of the most important area is Critical Reasoning in CAT Verbal section.
Last year 5 – 6 questions were based on the Critical Reasoning
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Important type of questions based on critical reasoning in CAT
1. Strengthening and Weakening
2. Essence of the passage
3. Inference based on passage
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If you are already familiar with CAT Critical Reasoning questions of the Assumption or Weaken type, mastering Strengthen problems will not present much of a challenge. This question type, usually straightforward, asks you to support a conclusion or a plan presented in the argument. Like its Weaken and Assumption counterparts, this question requires a clear analysis of the argument and a systematic critical evaluation of the answer choices.

How to recognize a strengthen question
You can be absolutely certain that you are dealing with a Strengthen problem if you see a question stem similar to one of the following:
Which of the following, if true, most strongly supports the conclusion above?
Which of the following, if true, does most to justify the researchers’ prediction?
Which of the following, if true, provides the best reason for believing that the new strategy will be successful?

Although easily recognizable, Strengthen questions can be confused with those that ask you to draw a conclusion or make an inference, which sometimes also use the word support (as in the argument above best supports which of the following statements?) However, they ask you to support one of the answers with the information IN the argument, whereas Strengthen questions require doing the reverse: instead of an answer choice supported BY the argument, you must find an answer choice that supports the argument.

How to analyze a strengthen argument

Like Assumption and Weaken problems, a Strengthen argument typically will consist of a premise or two plus a conclusion based on the information in the premises. Occasionally, the conclusion might be found in a question stem rather than in the argument itself, but this does not affect the logic of solving the problem.

The first step in effectively strengthening an argument is to identify its conclusion. Even though some questions might ask you to support the whole argument, not specifically its conclusion, remember that it is still the author’s opinion that we want to strengthen.

After you have separated the premises from the conclusion, look for a weakness in the reasoning. If you spot a potential flaw or a gap in the argument, you can strengthen its conclusion by selecting an answer choice with new information that at least partially closes this gap. Sometimes it helps to think of what assumptions the author makes and see whether any of them is unsupported. In those cases, you can strengthen the argument by proving that an assumption is actually valid.

Look at the following simple example:

Dietician: A kiwi contains twice as much vitamin C as an orange does. Nevertheless, those seeking to get their daily dose of Vitamin C from fruits do not need to replace oranges with kiwis in their diet.

Which of the following, if true, would lend the most support to the dietician’s conclusion?

A premise here is that a kiwi has more Vitamin C than an orange does. The dietician concludes, however, that people don’t need to replace oranges with kiwis. Is it clear from this argument why replacement isn’t necessary even though kiwis can supply more Vitamin C? No, so your goal is to find some additional information explaining why people may stick to oranges after all.

Another useful thing to know is that many arguments use information from analogies and surveys in their premises. In this case, answer choices that support the validity or soundness of such data are usually correct. For example, if the author makes a general conclusion based on information about a certain group of people, there’s always a possibility to attack this argument by claiming that the given group of people does not represent the majority. By contradicting that claim, you’ll strengthen the argument and protect it from such attacks.

How to pick the right choice

A correct answer choice will rarely make the conclusion one hundred percent true. Therefore, it is essential that you compare answer choices and pick the one that does the best job of strengthening the argument, even if it makes the conclusion only a little more likely to be true.

Look at the answer choices for the Kiwi versus Orange question:

A. Oranges also contain several other vitamins that are beneficial to human health.

B. In certain regions, kiwis might be harder to obtain than oranges.

C. Unlike that derived from oranges, Vitamin C from kiwis is easier for a human body to process.

D. An orange contains a necessary daily dose of Vitamin C.

E. Neither a kiwi nor an orange provides a sufficient daily dose of vitamin C.

Here the best choice is D because it explains why people need not necessarily switch from oranges to kiwis: a dose of Vitamin C from an orange is already enough and there is no need for more Vitamin C daily.

How to avoid the wrong choices

Typically wrong answers for Strengthen questions are like those for the Weaken type. They may have no tie to the conclusion, repeat the information presented in the premises, or attempt to explain why else a plan might work, but they fail to fix the weakness of the conclusion or validate the assumptions of the argument. Choices A and B in the kiwi/orange argument belong to this category; they explain why oranges are better than kiwis but without reference to Vitamin C.

Other wrong choices might go in the opposite direction and weaken the conclusion instead of strengthening it. Choices C and E above give reasons why kiwis may be preferred to oranges and therefore SHOULD replace oranges. Be careful with such options. Because of their seeming relevance to the conclusion, they can be very tempting, especially when you are under stress and pressed for time.

The last category of wrong answers includes those that appeal to your real-life experience. Remember, you are not assessing the plausibility of answer choices, or their real-life truthfulness; all that matters is the argument’s structure and the soundness of its reasoning.

In summary, you strengthen an argument in three simple steps:

1) Identify the argument’s conclusion.

2) Find the argument’s weakness or an unsupported assumption.

3) Pick the choice that best fixes the weakness or supports the assumption, avoiding those that contain irrelevant information or go in the wrong direction, and keeping in mind that you don’t have to prove the argument, just strengthen it.

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Weaken questions are the most frequently occurring problem type on the CMAT Critical Reasoning section. They usually ask you to do a fairly simple thing: find an answer that will undermine the argument offered in the question stem. Weakening an argument is, however, not as straightforward as it may seem. The key to cracking the Weaken question is a very clear understanding of what exactly it is that we want to challenge when casting doubt on an argument. That is the focus of this article. You will learn how Weaken questions usually look, what information you should look for in the right choice, and what answers to avoid.

How to recognize a weaken question

A Weaken question can ask you to undermine, challenge, or cast doubt on the validity of an argument. In its most basic form, it will sound like this:

Which of the following, if true, most seriously weakens the argument?

Sometimes, however, problems of this type might be formulated more obscurely. Consider the following questions:

Which of the following, if true, most strongly supports the view that the company’s new incentive program will not be successful?

Which of the following, if true, could be of the most use to the opponents of the new government policy?

These last two examples are both more specific and potentially more confusing. Despite positive-sounding language (most strongly supports, could be of the most use), they are still essentially Weaken questions, asking you to challenge the validity of a certain plan or policy.

How to analyze an argument

At the core of each typical Weaken question lies an argument; the author draws a conclusion based on stated premises. Weakening such an argument requires demonstrating that the author has failed to account for some circumstance or possibility that might alter the conclusion. Your goal is to follow the author’s logic and separate facts from opinion. Having done that, you usually will be able to identify conditions not stated in the argument that would have to be true for the conclusion to be valid. Ideally, isolating the conclusion from the premises should yield a couple of such assumptions. Consider the following argument:

A recent study has shown that, all other characteristics being equal, bilingual persons memorize more quickly and retain information longer than those who speak only one language. Clearly, learning several languages can be used as a way to improve memory.

The premise here is that a person who speaks two languages has a better memory than those who speak only one. On this basis, the author concludes that learning several (more than two) languages can improve memory. You would accept this conclusion only if you, like the author, assumed that good memory is the result of learning two languages and not the cause, and thatlearning several languages has the same effect as learning only two does.

An answer choice that tends to deny these assumptions will cast doubt on the argument’s conclusion. The correct answer choice will most likely introduce a new circumstance that makes the conclusion less likely to be valid. It is perfectly acceptable for Weaken answers to contain new information that was not included in the argument. The important thing is that this new piece of evidence should show that one or more of the author’s key assumptions might not be true. Let’s look at some possible Weaken answer choices for the above argument:

Which of the following most seriously weakens the conclusion above?

A. None of the bilingual participants in the study possessed particularly good memory before starting to learn a second language.

B. A study of those knowing several languages has shown that their memories are no better than those of monolingual persons.

C. Monolingual speakers usually score better on tests of spatial reasoning.

D. Most of the study’s participants who speak only one language have never tried to master another language.

E. Another study has revealed that the memory of those knowing several languages is only slightly better than that of bilingual persons.

In this case, Choice B casts the most serious doubt on the argument’s conclusion because it attacks the second assumption, that if knowing two languages helps improve memory so does knowing more than two languages.