Showing posts with label Reasoning. Show all posts
Showing posts with label Reasoning. Show all posts

Thursday, 18 September 2014

SYLLOGISM

Before you proceed, make sure you have read my article on Venn Diagrams.

Now Syllogism! I have seen 90% students 100% confused when it comes to Syllogism. I'll try to make this post as self-explanatory as possible, but for this to be effective you'll have to forget everything that you've read or learnt so far on this topic. Make a note of few points first :

1. We are going to use Venn diagrams to solve the questions but I won't be taking the usual "AEIO - universal particular" and what not route, because honestly Mujhe bhi nai aata wo samajh! And how does it matter what method you're using if you're getting the correct answer.
2. Don't solve any complicated faltu questions from 100 different websites, you're bound to get confused. For this particular topic, only & only solve from either an error-free book or past years' papers.
3. Don't get nervous if you're required to solve 4-statement or 1000-statement syllogisms. Sabme same Funda lagega!
4. My way of solving is not the conventional way, I use my own symbols while drawing Venn, but you can get used to them in 1 session, so no biggie!

 

Case - 1 & 2: These should be clear from the Venn.
Case - 3 : In the 2nd possibility, you can see that Venn is the same as for "All S are P". And you might be thinking that I'm wrong here - but I am not. Remember - "All" can be converted to "some" but "Some" cannot be converted to "All".
Case - 4 : Again this one is easy. Only thing is you have to rattafy all the 3 possibilities.

Now, the symbol that I was talking about. If you have to represent a "NOT" anywhere in syllogism you can do it as :
 
That little cross would help you in a big way. Here, it's evident that there's nothing common between Black and Green, and this also includes the area which is common between Black and White. What does that tell us?
That ---->> Some White are NOT green.
Also, there's no cross linking White and Green. And what does that tell us?
That ---->> Some whites are green is a possibility. Isn't it? Yes it is.

See? The 4 cases that we discussed and this little cross : That covers all of syllogism! Now we have to apply these and some brains and we can solve any question on this topic. But again, I'm warning you - Don't go solving faltu questions which are extremely twisted! Neither any Bank nor SSC is looking for Einsteins!

EXAMPLES

1. Statements - Some dews are drops.
                         All drops are stones.
    Conclusions - At least some dews are stones.
                           At least some stones are drops.
Solution : Don't get anxious if you see unexpected words like "at least" , "maybe" , "possibility" in these questions. Whatever be the variation in the question, we have to apply the same rules and answer as per the basic English meanings of these words. So here, the answer would be : Both conclusions follow.
You can very well see in the diagram, that wherever we place drops, it will be inside stones (as per 2nd statement) ---->> This  explains Conclusion 1.
Conclusion 2 is directly derived from Statement 2.

2. Statements - Some squares are Circles.
                        No circle is a triangle.
                        No line is a square.
    Conclusions -  All squares can never be circles.
                            Some lines are circles.
Solution : Conclusion 1 follows because there is some part of squares that's common with triangles. And considering statement 2 , that cannot happen.
Conclusion 2 doesn't follow because it's not definite. If the statement would have been "some lines may be circles" then it would have followed.

3. Statements - Some leaves are skies.
                        Some skies are clouds.
                        No cloud is a boat.
   Conclusions  -I. Some boats are definitely leaves.
                          II. At least some clouds are leaves.
                         III. All skies being leaves is a possibility.
                         IV. No leaf is a boat.
   Options : a) I, II and III follow
                   b) II, III and IV follow
                   c) Either I or IV and II follow
                   d) Either I or IV and III follow
 Solution : D is the correct answer. All skies can be inside the leaves circle, this will not contradict with any of the other statements, It is a possibility!! Therefore, conclusion III follows. As for I & IV --->> Dono me se ek to hoga hi na! Either leaf & boat don't have common area ya fir they do.
Conclusion II will not follow because again, it's not definite that some clouds are leaves. If there was a "maybe" or a "possibility" used here, then it would have followed. But the conclusion uses -->> At least some clouds ARE leaves.




That's all for now, since Syllogism has a lot of variations , I'll try to generalise them and post another article with examples from each variation with explanation. Until then, try solving questions (only from reliable sources) and you can leave your doubts in the comments!!

Tuesday, 16 September 2014

VENN DIAGRAMS

My general awareness was somewhat poor and so to maintain the balance I worked really hard on Reasoning. I attempted 44/50 questions in SBI PO with 90% accuracy in a span of 35minutes. Now before you get any ideas, there's simply no tricks or shortcuts in Reasoning, there's only practise. Even so, I'm going to share how I handle each and every topic when it comes to Reasoning. Let's start with Venn Diagrams.


What are Venn Diagrams?
They are figures representing group of items in the form of circles (mostly).

Can I expect these questions?
Direct questions on Venn diagrams won't be asked in any of the SBI exams. You might find them in IBPS or SSC CGL. But we will be using these to solve syllogism questions in the next article, and questions on syllogism are asked in every exam, that too worth atleast 5 marks.

Situation - 1
When 1 group is completely included in the 2nd and 2nd is completely included in the 3rd. For eg. Guitarists, instrumentalists, musicians

Situation - 2
When 2 groups are unrelated to each other but are completely included in the 3rd. For eg. carrot, pumpkin, vegetable

Situation - 3
When 2 groups have something in common and both are completely included in the 3rd. For eg. Mothers, sisters, females. Some mothers can be sisters too and vice versa.

Situation - 4
When 1 group is completely included in another, while 3rd group is unrelated to both of them. For eg. Indians, Asians, Europeans

Situation - 5
When all 3 groups are related in some way but cannot be completely included in each other. For eg. Illiterate people, unemployed people, poor people. We can have a combination of any 2, and we can even have a combination of all 3.

Situation - 6
When 2 groups are unrelated to each other but they are both somewhat related to the 3rd. For eg. Police, Doctor, Female. We can have Female policemen and female doctors but police and doctors don't have anything in common.

Situation - 7
When 1 is completely included in the 2nd and both of them are party related to the 3rd. For eg. Females, Nieces, cousins. All nieces can only be females, but there can be female cousins and some female cousins can also be somebody's niece.

Situation - 8
If 1 group is partly related to the 2nd group and 3rd is completely unrelated to both of them. For eg. Students, scholars , books. Some students can be scholars but neither of them can be a book!

Situation - 9
When all 3 are completely unrelated. For eg. Sun, Pluto, Earth. Now, if there was another group "Planets" then Pluto and Earth would fit in there, but we can't add things of our own will, right?!



That's all the possibilities there can be while using Venn Diagrams. In case you're confused, just refer to the picture posted above, I'm sure it will clarify things for you.

QUESTIONAIRE
There's mainly 3 kinds of questions on Venn diagrams. I am posting sample questions on each of the 3. The answer keys have been added. Happy solving! :))


                                  



 
ANSWERS
21-C 22-A 23-C 24-B 25-C 26-C
31-E 32-D 33-E 34-C 35-A 36-B 37-C 38-E 39-D
9-B 10-D 11-D 12-A

Check out my article on Syllogism