Logical Reasoning - Logical Deduction - Discussion
Discussion Forum : Logical Deduction - Section 1 (Q.No. 15)
Directions to Solve
In each question below are given two statements followed by two conclusions numbered I and II. You have to take the given two statements to be true even if they seem to be at variance from commonly known facts. Read the conclusion and then decide which of the given conclusions logically follows from the two given statements, disregarding commonly known facts.
Give answer:
- (A) If only conclusion I follows
- (B) If only conclusion II follows
- (C) If either I or II follows
- (D) If neither I nor II follows and
- (E) If both I and II follow.
15.
Statements: All fishes are grey in colour. Some fishes are heavy.
Conclusions:
- All heavy fishes are grey in colour.
- All light fishes are not grey in colour.
Answer: Option
Explanation:
Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that 'Some heavy things are grey in colour'. I is a cumulative result of this conclusion and the first premise. Thus, only I holds.
Discussion:
39 comments Page 1 of 4.
Anisha said:
9 years ago
All those people who claim that A is the correct answer are wrong. The reason is because of this:
The answer SHOULD start from "Some" and SHOULD NOT have the middle term (fishes) at all.
The answer would be: Some heavy things are grey. Some grey things are heavy. [These 2 sentences are converse of each other.]
Why? Because check "Case 5'' in this link: http://www.indiabix.com/logical-reasoning/logical-deduction/formulas
That diagram's Venn diagram is how the Venn diagram should be.
Yes, a statement I is "grammatically and logically" correct. But that's not the conclusion because it is simply rephrased. We are here to find the logical deduction, not to rephrase the question based on a Venn diagram. If that's what we have to do, then all other answers should also follow "rephrasing" instead of "deducing". Hence, the explanation is vague.
D is the correct answer. I am 300% sure.
The answer SHOULD start from "Some" and SHOULD NOT have the middle term (fishes) at all.
The answer would be: Some heavy things are grey. Some grey things are heavy. [These 2 sentences are converse of each other.]
Why? Because check "Case 5'' in this link: http://www.indiabix.com/logical-reasoning/logical-deduction/formulas
That diagram's Venn diagram is how the Venn diagram should be.
Yes, a statement I is "grammatically and logically" correct. But that's not the conclusion because it is simply rephrased. We are here to find the logical deduction, not to rephrase the question based on a Venn diagram. If that's what we have to do, then all other answers should also follow "rephrasing" instead of "deducing". Hence, the explanation is vague.
D is the correct answer. I am 300% sure.
(3)
Anshu ranjan said:
10 years ago
Middle word should not be there in conclusion. So answer is D and also one particular premise gives the particular conclusion and even if we converse the conclusion or by conversion of any other premises we don't able to get the required conclusion. So answer should be some heavy things are grey in color.
Bhushan said:
1 decade ago
If a term is not distributed in premise, it should not be distributed in conclusion. Heavy is not distributed according to second premise,so it shouldn't be distributed in conclusion.In 1st conclusion heavy is distributed.So it is not valid.Hence answer is D.
Somesh more said:
8 years ago
The answer to this question is d.
As conclusion 2 fails because there is nothing mentioned about light fishes.
And one fails because it is not mandatory that all heavy should be grey, if it was "some heavy are grey" then conclusion one would follow.
As conclusion 2 fails because there is nothing mentioned about light fishes.
And one fails because it is not mandatory that all heavy should be grey, if it was "some heavy are grey" then conclusion one would follow.
Rajesh Jha said:
1 decade ago
Answer should be D. Because to have a Universal positive conclusion we need to have both the sentences to be universal positive.
And the Rule of Either 1 or 2 also can not be applied as the subject and predicates are not same. Hence only D.
And the Rule of Either 1 or 2 also can not be applied as the subject and predicates are not same. Hence only D.
Riddle42 said:
9 years ago
The right answer is A.
We know the statements: Some fishes are heavy. ALL (including all of them that are heavy) fishes are GREY in colour. So that makes conclusion number one right.
1. All heavy fishes are grey in colour.
We know the statements: Some fishes are heavy. ALL (including all of them that are heavy) fishes are GREY in colour. So that makes conclusion number one right.
1. All heavy fishes are grey in colour.
Saurabh choudhary said:
1 decade ago
As color is non distributive and heavy fishes are non distributive. And statement B is particular therefore conclusion will be.
Some heavy fishes are grey in color.
So D will be the answer.
Some heavy fishes are grey in color.
So D will be the answer.
Rocky said:
1 decade ago
According to the rule of syllogism, the middle term should not be there in the conclusion. Here fishes is the middle term. So the conclusion should not contain the middle term.
Prashnath said:
5 years ago
Yes, the answer is correct. I agree with you bro @Bill. Whether it is heavy or light fish doesn't matter. In question only given all fishes are grey, hence A is correct.
Trishul said:
1 decade ago
@Ako Venuh,
Fishes is the middle term but heavy fishes is not the middle term. Heavy fishes is a completely distributed subset of both fishes and heavy.
Fishes is the middle term but heavy fishes is not the middle term. Heavy fishes is a completely distributed subset of both fishes and heavy.
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