## Doubts of the Venn Diagram type logic

Post your doubts pertaining to LR class sheets and Basic Reference books.

### Doubts of the Venn Diagram type logic

Post your doubts of Venn diagram sheet here

Posts: 228
Joined: Wed Feb 13, 2013 5:51 am

### Re: Doubts of the Venn Diagram type logic

question 53 nd 59, i got answer by venn-diagram approach, can you explain by the mechanical approach??/
tpsriram

Posts: 39
Joined: Wed Feb 27, 2013 8:43 am

### Re: Doubts of the Venn Diagram type logic

sir my doubts are:
30,40,72
gaurav1399

Posts: 48
Joined: Wed Feb 27, 2013 7:49 am

### Re: Doubts of the Venn Diagram type logic

53. No handsomes are beauties
All beauties are brutes.
(a) Some brutes are not handsomes.
(b) No handsomes are brutes.
(d) None of the above.

Solution

Rule 1 - middle term or the common term is distributed - Beauties is distributed in both the sentences

Rule-2 - The remaining terms are handsomes (distributed in the first sentence) and Brutes (which is not distributed).

Rule-3 - Nature of conclusion - One of the main sentences is positive and the other is negative- there fore the conclusion shall be negative. The negative conclusion such that one of the terms is distributed and the other is not must be of the form

"Some ...........are not .............."

In the above statement, the subject is distributed and the predicate (property) is not distributed. Thus replacing subject by "Brutes" and the predicate by "Handsomes" we get

Some brutes are not handsomes

Q59 is identical to this one - hope you understood it now

Posts: 228
Joined: Wed Feb 13, 2013 5:51 am

### Re: Doubts of the Venn Diagram type logic

30. If the food is not tasty, then I will not go to cinema nor will
I have dinner.
(a) If I have gone to cinema or I have not had dinner,
then the food is not tasty.
(b) If I have gone to cinema and I had dinner, then the
food is tasty.
© If I have gone to cinema and I have not had dinner,
then the food is tasty.
(d) If I have gone to cinema or I have had dinner, then
the food is tasty.
Solution

The main statement is of the form - If "A", then neither "B" nor "C"
Logically speaking the above statement implies - If A exists, B does not exist and C does not exist.
Thus if atleast one of the two events B or C exists, the event A can not exist.

Only Option D fulfills the criteria - It says that B or C exists - which is equal to saying that atleast one of the two events exist - Therefore A can not exist.

40. Some pins are tins. Some tins are not shins. So
1. Some shins are not pins.
2. Some pins are not shins.

Solution
Both the statements are particular - therefore no conclusion exists - Answer option "d""

72. (A) Regular exercise is necessary for every hard-working
person.
(B) Regular exercise is a panacea for all ills of the
body.
© Regular exercise is a must for a person whose
daily routine or work is sedentary.
(D) There is no exercise-culture in India.
(E) regular exercise can make a person fit and
healthy whether a sedentary worker or not.
(F) Regular exercise prepares a man for hard work.
(a) BCF (b) ABC © EFA (d) ACE

Solution
Regular Exercise is necessary for both hardworking person and the person whose lifestyle is sedentary - therefore statements A and C should be followed by E.

to approach such questions go straight to options and seek answers from the options. For example if you choose option A - then statements B and C must be followed by statement F.
A mere look at statements B and C suggests that these may not follow F - Hence the answer