Syllogism by Rules Part 4: Solving 3 or more statements in one go by rules

Shortcut to solve syllogism by rules

Day 4: Solving 3 or more statements in one go by rules

 

Example: Some A are B + All B are C + All C are D.
Method 1: Take first 2 proposition: We have Some+ All = Some
Then this Some with the last proposition i.e Some +All= Some.
Hence We have Some A are D is the conclusion.

Method 2: Take 2nd and 3rd proposition i.e All+ All = All
Now solve it with first proposition Some+All=Some => Some A are D

In both case we get the same answer. But there are some cases where you have to follow a sequence in solving the proposition to get the conclusion. Let’s have a look on the next example.

We will discuss again about this irregularity and a special case related to it on the last day.

Solved Examples:

1) Statements: (a) Some A are B.  (b) All C are B.  (c)Some C are D.  (d)No E is C.
Conclusions: 
I. Some B are not E.
II. No B is D
A) only I follows
B) only II follows
C) either I or II follows
D) neither I nor II follow
E) both I and II follow

View Answer
  Option A
Explanation
: In (I) we have to check conclusion between E and B. So see which propositions do we need as per the FIRST & LAST RULE. We have B in two statement, (a) and (b) while we have E in proposition (d). Note that the common entity between (b) and (d) is C. So we need just (b) and (d)
Solve in the order (d)+ (b) so that FIRST & LAST RULE is followed. No + ALL= Some Not reversed. Some B are not E. So (I) is true.
(II) we need to find relation between B and D. We need only proposition (b) and (c) for this
Take Reverse (c) + (b) = Some D are C + All C are B= Some D are B. Hence (II) is false

2) Statements: All A are B. Some C are B. Some C are D. Some E are C.
Conclusions: 
I. Some A are C
II. No B is D
A) only I follows
B) only II follows
C) either I or II follows
D) neither I nor II follow
E) both I and II follow

View Answer
  Option D
Explanation
: For (I): (a) + reverse(b) = All + Some  No Conclusion between A and C. So I is false
(II): reverse(b)+(c)= Some+ Some= No conclusion between B and D. So II is false

3) Statements: Some A are B. All B are C. Some B are D. Some E is D.
Conclusions: 
I. Some A are C
II. No E is A
A) only I follows
B) only II follows
C) either I or II follows
D) neither I nor II follow
E) both I and II follow

View Answer
  Option A
Explanation
: For (I): (a)+(b)= Some+All= Some = Some A are C is true. So I follows
(II): (a)+(b)+(c)+reverse(d)= Some+All+Some+Some  => solve one by one in mind.. Some+All= Some then add it to next Some, Some +Some No conclusion. Stop here. So there is no definite conclusion between A and E. So II doesnot follows.

Topic for Day 5: All the cases of possibility and Condition of Complementary Pair (EITHER-OR)

Ask your doubt in comment section.

Thank You!!!!!
 

 

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32 Thoughts to “Syllogism by Rules Part 4: Solving 3 or more statements in one go by rules”

  1. ANUP SINGH

    https://uploads.disquscdn.com/images/415260eb24239bf5f8d264844a1b8d8d79b077e128712e0b0cc069d04bb3e059.jpg

    method 2——-All B are C+All C are D=All B are D
    Some A are B+All B are D=Some A are D

    1. Suraj

      isme doubts hai?

      1. ANUP SINGH

        NO SIR, typo error h isme, kisiko prob na ho isly point out kia.

        1. Suraj

          acha ha,, ty .. got it

          1. ANUP SINGH

            sir preference matter krta h?
            n if preference selection is wrong then would it affect our soln?

          2. Suraj

            ha preference matter karta hai.. jaisa ki example 6 me hai.. bas dhyaan ye dena hai ki pehle un propositions ko solve karo, jisme some not wala conclusion naa aye.. as in example 6…aise case bohot kam hi milenge,, but keep this logic in mind

          3. ANUP SINGH

            no sir i was actually asking: like we prefer “SOME” to “ALL”, and “NO” to “ALL”. If we prefer “ALL” to “SOME/NO”, then will it affect our solution?

          4. Suraj

            ha statement ko reverse karne me ye logic follow karna padega..
            example
            SOme A is B
            All A is C

            Now when we reverse SOme A is B => SOme B is A
            Add it to second statement Some B is A + ALl A is C => SOme B is C (is the conclusion)

            Now if we reverse second we get : Some C is A
            Add it to Some A is B
            Come C is A+ SOme A is B => we get no conclusion

            so prefernce matters
            first method is correct

          5. ANUP SINGH

            perfect sir, now no more doubts from today’s post. ty

          6. Suraj

            as in this
            SOme A are B. All B are C. Some C are D. All D are E

            is case me kisi bhi order me solve karo,, same ans ayega.. kyunki isme kisi me bhi SOME NOT wala case nhi ayega

            aur isme

            No A is B. All B is C. All C is D

            isko 2 tarike se kar sakte hai.. ya to pehle first two ko karo,, usme SOme not revsred ka case ban rah..
            second way is that ki last two ko solve karo,, usme sirf All ka case banega then add it to first proposition.. So the correct method is 2nd one..

          7. Yogi ji

            Some C are not a

      2. garima shah

        Hello sir …..sir 1st question me hm b+d bhi kr skte h?? .
        Some b are c+no C are E..>>
        SO Some B are not E bhi correct hoga???

        1. Suraj

          yes it is correct..
          agar kisi conclusion me B and E ka relation pucha hota,, then iski zarurat padti… then suppose ki COnlcuion given hota
          i . Some B are E
          ii. SOme E are not B
          iii. Some B are not E

          to only iii follow krta…

          1. garima shah

            Statement:
            (a)Some Samsung are Phone
            (b) No Samsung is Vivo.
            Conclusion:
            (i) Some Vivo are not phone
            (ii) Some Phone are not Vivo
            (iii) No Vivo is samsung
            A) (i) and (iii)
            B) (iii)
            C) (ii) and (iii)
            D) (ii)
            E) All

            Sir is question me apne both correct btaya h …but mera only 2nd correct ho RHA h…..
            I reversed to 2nd statement …so..
            No vivo is Samsung+some Samsung is phone …
            To sir by rule only 2nd hi sahi hoga tb???No + some >>> some not reverse??? Pls clarify it sir…

          2. Suraj

            isme to sirf ii follow krega,, where have i mentioned both?? give me the link, i will edit it

          3. garima shah

            Sorry Sir WO mujhe kl nhi samjh me aya tha but aaj aa gya…..thanx….

          4. Suraj

            wait..see my above rely both 2 and 3 follow krega

          5. Suraj

            isme both 2 and 3 follow krega…. 2 wala to u did right..

            and 3 by the reverse of statement b

          6. garima shah

            Sir I think there is no need of copy nd pen we can solve syllogism mentally

          7. Suraj

            yes right.. only sentence arrange ho jaye then its very simple

          8. garima shah

            Sorry sir aa gya samjh me aa gya ..actually mujhe kl nhi samjh me aa RHA tha …but ab aa gya….thank you so much sir for these short tricks …..it will surely take less time ……

  2. Yogi ji

    Suraj bhut si mistake hti hai quiz main. Like yesterday in reasoning puzzle

  3. Suraj

    Questions for Practise for Syllogism By rules

    1. Statements: All cones are cylinders. All cylinders are squares. No square is a rectangle.
    Conclusions:
    I. No rectangle is a cone
    II. No cone is a square
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    2. Statements: No apple is orange. All grapes are oranges. Some apples are sweet.
    Conclusions:
    I. No apple is grape
    II. Some oranges are apples.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    3. Statements: All white are black. Some red are black. No black is green.
    Conclusions:
    I. Some green are red.
    II. Some red are not green
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    4. Statements: Some boys are smart. Some smart are girls. All girls are pretty.
    Conclusions:
    I. All girls being boys is a possibility.
    II. Some pretty are not boys.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    5. Statements: Some planes are rails. No metro is a plane. All busses are rails.
    Conclusions:
    I. Some rails are not metro.
    II. All busses being planes is a possibility
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    6. Statements: All principals are students. Some teachers are students. All mothers are teachers.
    Conclusions:
    I. All teachers are mothers.
    II. No principal is teacher.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    7. Statements: No gold is silver. Some platinum is gold. Some diamonds are silver.
    Conclusions:
    I. Some diamonds are not gold.
    II. All platinum being silver is a possibility.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    8. Statements: All blue are white. No white is a black. All black are red.
    Conclusions:
    I. No blue is a black.
    II. Some red is white.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    9. Statements: All Lions are tigers. All monkeys are tigers. Some tigers are cat.
    Conclusions:
    I. Some monkeys are Lions.
    II. Some cats are monkeys.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    10. Statements: Some crickets are footballs. Some footballs are hockey. All hockey are tennis.
    Conclusions:
    I. No hockey is a cricket.
    II. Some tennis are footballs.
    A) only I follows
    B) only II follows
    C) either I or II follows
    D) neither I nor II follow
    E) both I and II follow

    1. Suraj

      Answers

      Ans 1) Option A
      Ans 2) Option A
      Ans 3) Option B
      Ans 4) Option A
      Ans 5) Option E
      Ans 6) Option D
      Ans 7) Option A
      Ans 8) Option A
      Ans 9) Option D
      Ans 10) Option B

  4. sachin shukla@Target sbi po

    good ))thanku sir

  5. Stoic

    @surajskt:disqus sir
    2nd ques me agar (b)+ (a) ko reverse kr den mns ALL B are A kren to Some C are A hoga den iska reverse Some A are C hoga to yeh true nhi hona chahie?

    1. Suraj

      plz post the full question here and tell which statement u want to reverse

      1. Stoic

        Statements: All A are B. Some C are B. Some C are D. Some E are C.
        Conclusions:
        I. Some A are C
        II. No B is D
        A) only I follows
        B) only II follows
        C) either I or II follows
        D) neither I nor II follow
        E) both I and II follow
        #now sir got it pehle maine ALL k reverse kr dia t jo k hota hi nhi h wo some me hota jata now corrected .No doubt..Sorry

      2. Stoic

        sir ek query aur t plzz check ur inbox..possibility wali

      3. PHENOMENAL

        Thank u all doubts cleared

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