Question

In a recently held parent-teacher meeting, the teachers had very few complaints about Ravi. After all, Ravi was a hardworking and kind student. Incidentally, almost all of Ravi's friends at school were hardworking and kind too. But the teachers drew attention to Ravi's complete lack of interest in sports. The teachers believed that, along with some of his friends who showed similar disinterest in sports, Ravi needed to engage in some sports for his overall development.
Based only on the information provided above, which one of the following statements can be logically inferred with certainty?

• A. All of Ravi's friends are hardworking and kind.
• B. No one who is not a friend of Ravi is hardworking and kind.
• C. None of Ravi's friends are interested in sports.
• D. Some of Ravi's friends are hardworking and kind.

Hint:

In inference questions, pay close attention to quantifiers like "all," "some," "none," "most," and "almost all." A statement with "all" can be disproven by a single counterexample. A statement with "some" is much easier to prove. If "almost all X are Y," it is always true that "some X are Y."

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This question requires making a logical inference based strictly on the provided text. An inference is a conclusion that can be drawn with certainty from the given information, without making any outside assumptions.
Step 2: Detailed Explanation:
Let's analyze the key statement from the passage: "almost all of Ravi's friends at school were hardworking and kind too."
Now let's evaluate each option based on this statement:
- (A) All of Ravi's friends are hardworking and kind. The passage says "almost all," which implies that most are, but perhaps not every single one. Therefore, we cannot be certain that "all" of them are. This statement is not a certain inference.
- (B) No one who is not a friend of Ravi is hardworking and kind. The passage gives information only about Ravi and his friends. It says nothing about people who are not Ravi's friends. Making a conclusion about this group is an overgeneralization and cannot be inferred.
- (C) None of Ravi's friends are interested in sports. The passage states that Ravi needed to engage in sports "along with some of his friends who showed similar disinterest in sports." This directly implies that at least "some" of his friends are not interested in sports, but it doesn't mean "none" are. There could be other friends who are interested in sports. This statement is not certain.
- (D) Some of Ravi's friends are hardworking and kind. The passage states "almost all" of his friends have these qualities. The term "almost all" logically implies that "some" of them definitely do. If almost all are, it is mathematically certain that at least some are. This statement can be inferred with certainty.
Step 3: Final Answer:
The only statement that can be logically inferred with certainty is (D).
Step 4: Why This is Correct:
The quantifier "almost all" is a subset of "all" but is a superset of "some". If a property is true for "almost all" members of a group, it is logically guaranteed to be true for "some" members of that group. The other options make claims that are either too strong (all, none) or go beyond the scope of the provided information.