SET

This is a very important topic in the GRE and questions on this topic often come up when the candidate is doing pretty well in their quant section on the test day. So, this can be regarded as a harder topic. However, it cannot be ignored totally as it may come up in any difficulty level even in easy level (however, we have analyzed the trend and questions on SET appears more after a student has performed fairly well in the first section of Quant).

But there is nothing to feel intimidated (Syn: daunted/timorous/timid/diffident/cautious). We will try to explicate (Syn: Explain) this convoluted (Syn: Involved) chapter topic wise. So first we will start with the basics of SETS.Definition:A set is a group of distinct elements and is denoted by {}. So if department is a set consisting of X, Y, Z candidates then we can refer that department={X, Y, Z}. One important point to note is that SET can only contain DISTINCT element. Thus {X, X, Y, Z} is not a set at all. This is a very important concept and is tested by ETS in GRE topics like SET, Statistics. A SET can even be empty and can also be null (Note: empty set and null set are different. Not imp from GRE perspective. However for any query on this, feel free to contact us).Intersection and Union:Now, we know what a set is. We can say without any doubt that {1, 2, 3} is a set A and {2, 3, 4, 5} is a set B.So, what can be deduced from the above 2 sets. We can see that there are few elements that are common to both the set. In Statistical term we say it as an Intersection of 2 sets (n).So intersection of set A and set B (AnB) is {2, 3}. There is another term called Union (u). Union of sets is a set which contain all the elements of the respective sets. So union of set A and set B (AuB) is {1, 2, 3, 4, 5} (as mentioned set contains distinct elements so no duplicate value exists). It is worth mentioning that the intersection and union of more than one set is also a set.

Venn Diagrams:

Set can be very efficiently represented using Venn diagram. Below are the Venn Diagrams for set A, B, AuB and AnB and are self-explanatory.

Problem solving becomes real easy using Venn diagrams. However we will focus on Venn diagrams when we will look into problems containing more than 2 sets. Another point to be noted is that Venn diagram is good in representing the total number of quantities, not the individuals.Question Types:SET question types can be categorized into many classes. However, in GRE SET questions can be categorized into 2 types:

1) Questions having 2 sets (Easy/Medium Questions).2) Questions having more than 2 sets (Generally 3 sets). (Medium/Hard Questions)We must strategize ourselves to deal the above type of questions. We will discuss The Dual Matrix Approach for the questions having 2 sets and The Venn Diagram Approach for questions having more than 2 sets, in our upcoming blogs.

Check out the following videos for reference :

http://www.youtube.com/watch?feature=player_detailpage&v=En8fI2ixepohttp://www.youtube.com/watch?v=YAjxRUGS0Gc

Till then Happy Learning!!!!For any assistance we are there to help. Follow us here:http://tinyurl.com/ndbvpdo