CBSE Class 11-science Answered

A Venn diagram uses overlapping circles  to illustrate the logical relationships between two or more sets of items.

Venn diagram serve to graphically organize things, highlighting how the items are similar and different.

Venn diagrams are used to think through and depict how items relate to each within a particular “universe” or segment.

Venn diagrams allow users to visualize data in clear, powerful ways.

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Let us consider a library that has 300 members. Let this library has books in three languages i.e. English , Hindi and Marathi.

In the figure Readers of english language books are represented by a circle that has Letter E .

Readers of Hindi language books are represented by a circle that has letter H .

Readers of Marathi language books are represented by a circle that has letter M .

Region of overlapped circles indicate the readers of mixed language books.

Let 20 readers are reading books of all three languages. Hence number 20 is indicated to the area common to all circle (Light Yellow colour) .

Let 80 memers read both english and hindi books . Since 20 memebers read all language books , then (80-20) = 60 members read both english and hindi books.

Hence the area common to english books and hindi books (green colour) is shown as 60 members .

Let 50 memers read both english and marathi books . Since 20 memebers read all language books , then (50-20) = 30 members read both english and marathi books.

Hence the area common to english books and marathi books (rose colour) is shown as 30 members .

Let 60 memers read both marathi and hindi books . Since 20 memebers read all language books , then (60-20) = 40 members read both marathi and hindi books.

Hence the area common to marathi books and hindi books (violet colour) is shown as 40 members .

Let 150 members are reading english books and some of these 150 members read other languages also.

If we are interested to find the number of readers who read only english , then we get this number by subtracting the number of readers who read other language books in addition to english.

number of readers who read only english = 150 - (60+20+30) = 40

Hence number 40 is marked in yellow color region that represents readers of only english books.

Let 170 members are reading hindi books and some of these 170 members read other languages also.

If we are interested to find the number of readers who read only hindi , then we get this number by subtracting the number of readers who read other language books in addition to hindi.

number of readers who read only english = 170 - (60+20+40) = 50

Hence number 50 is marked in gold color region that represents readers of only hindi books.

Let 110 members are reading marathi books and some of these 110 members read other languages also.

If we are interested to find the number of readers who read only marathi , then we get this number by subtracting the number of readers who read other language books in addition to marathi.

number of readers who read only english = 110 - (30+20+40) = 20

Hence number 20 is marked in blue color region that represents readers of only marathi books.

There are some members who do not read any books . To find the number of members who do not read any books ,

we subtract numer of memebrs who read atleast one language from total members 300 .

number of members who do not read any books = 300 - ( 20+60+40+30+40+50+20) = 40 .

This number 40 is marked in a region of universe ( white color )  that has excluded the region of circles .

This example explains how to represent the relationship between different sets , using circles and overlapping area of circles.