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Question

Two statements are given, followed by two conclusions numbered I and II. Assuming the statements to be true, even if they seem to be at variance with commonly know facts, decide which of the conclusions logically follow(s) from the statements.

Statements:

All wires are motors.

All motors are pumps.

Conclusions:

i. All wires are pumps.

ii. Some motors are wires.

The correct answer is

Both the conclusions i and ii follow

Logical Reasoning: Analyzing Statements and Conclusions

This question falls under the category of Logical Reasoning, specifically dealing with Syllogisms or Deductive Reasoning. We are given two statements and two conclusions, and we need to determine which conclusion(s) logically follow from the given statements, assuming the statements are true.

Given Statements

  1. All wires are motors.
  2. All motors are pumps.

Given Conclusions

  1. All wires are pumps.
  2. Some motors are wires.

Analyzing the Statements Using Logical Deduction

Let's represent the categories:

  • W = Wires
  • M = Motors
  • P = Pumps

Statement 1 says "All W are M". This is a universal affirmative proposition. It means that the set of Wires is entirely contained within the set of Motors.

Statement 2 says "All M are P". This is also a universal affirmative proposition. It means that the set of Motors is entirely contained within the set of Pumps.

We can visualize this relationship like nested sets or use syllogistic rules:

Statement 1: All W $\rightarrow$ M

Statement 2: All M $\rightarrow$ P

When we combine these two statements, we can see a direct link between W and P through M. If every Wire is a Motor, and every Motor is a Pump, then it logically follows that every Wire must also be a Pump.

Consider the conversion of universal affirmative propositions. The conversion of "All A are B" is "Some B are A". This conversion is valid for "All A are B". So, from Statement 1, "All wires are motors", we can logically infer "Some motors are wires".

Evaluating the Conclusions

Conclusion i: All wires are pumps.

Based on our analysis:

  • All W are M (Statement 1)
  • All M are P (Statement 2)

Combining these, we get: All W are P.

This conclusion perfectly matches our deduction from the combined statements. Therefore, Conclusion i logically follows from the given statements.

Conclusion ii: Some motors are wires.

Based on our analysis of Statement 1:

  • Statement 1 is "All wires are motors".

The valid conversion of "All wires are motors" is "Some motors are wires". If every single wire is a motor, then within the group of motors, there must be at least some motors that are wires (specifically, all the wires). Therefore, Conclusion ii logically follows from Statement 1.

Conclusion Summary

Both Conclusion i (All wires are pumps) and Conclusion ii (Some motors are wires) logically follow from the given statements.

Revision Table: Logical Reasoning Concepts

Term Description Example (from question)
Statement A proposition assumed to be true for the purpose of deduction. All wires are motors.
Conclusion A proposition derived logically from the statements. All wires are pumps.
Syllogism A form of deductive reasoning where two statements (premises) lead to a conclusion. Statement 1 + Statement 2 $\rightarrow$ Conclusion i
Universal Affirmative (A type) A statement of the form "All A are B". All wires are motors.
Particular Affirmative (I type) A statement of the form "Some A are B". Some motors are wires.
Conversion Interchanging the subject and predicate of a proposition. Valid for A type (All A are B becomes Some B are A). "All wires are motors" converts to "Some motors are wires".

Additional Information: Understanding Syllogisms

Syllogisms are a fundamental part of deductive reasoning. They consist of two premises (statements) and a conclusion. The validity of a syllogism depends on its structure, not the truthfulness of the premises in the real world. In these types of logical reasoning problems, we strictly follow the given statements.

The structure encountered here is a classic valid syllogism form:

  • All A are B.
  • All B are C.
  • Therefore, All A are C.

In our question:

  • A = Wires
  • B = Motors
  • C = Pumps

So, "All wires are motors" and "All motors are pumps" logically leads to "All wires are pumps". This confirms Conclusion i.

Conclusion ii relies on the immediate inference through conversion. From "All A are B", we can always infer "Some B are A". This is because if the entire set A is inside the set B, then the elements of A are a part of B, and those elements are also A. Hence, there are some elements in B that are A.

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Important Questions from Conventional Syllogism

  1. Read the given statements and conclusions carefully. Assuming that the information given in the statements is true, even if it appears to be at variance with commonly known facts, decide which of the given conclusions logically follow(s) from the statements.

    Statements:

    1. Some flowers are chemicals.

    2. Some chemicals are herbs.

    Conclusions:

    I. No flower is a herb.

    II. Some flowers are herbs.

  2. Read the given statements and conclusions carefully. Assuming that the information given in the statements is true, even if it appears to be at variance with commonly known facts, decide which of the given conclusions logically follow(s) from the statements.

    Statements:

    All students are teachers.

    All teachers are professors.

    Conclusions:

    1. All students are professors.

    2. All professors are students.

    3. No teacher is a professor.

  3. Read the given statements and conclusions carefully. Assuming that the information given in the statements is true, even if it appears to be at variance with commonly known facts, decide which of the given conclusions logically follow(s) from the statements.

    Statements:

    I. Some dentists are surgeons.

    II. All the surgeons are doctors.

    Conclusions:

    I. Some dentists are doctors.

    II. No surgeons are dentists.

  4. The statements below are followed by two conclusions labelled I and II. Assuming that the information in the statements is true, even if it appears at variance with generally established facts. decide which conclusion(s) logically and definitely follow(s) from the information given in the statements.

    Statements:

    1) Some angers are griefs.

    2) Some griefs are loves.

    Conclusion:

    I. Some griefs are angers.

    II. Some loves are griefs
  5. The statements below are followed by three conclusions labeled I, II and III. Assuming that the Information in the statements is true, even if it appears to be at variance with generally established facts, decide which conclusion(s) logically and definitely follow(s) from the information given in the statements.

    Statements:

    All balls are boats.

    All boats are cars.

    Conclusions:

    I. Some cars are balls.

    II. All balls are cars.

    III. All cars are balls.

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