Here we have given the solutions of some important questions of chapter 1 (Set Theory) of NCERT Exemplar book .

Short answer type questions

**1. Write the following sets in the roaster form**

**(i)**

**(ii)**

**(iii)**

**Sol. (i) **On solving the equation , we get

Thus .

**(ii) **gives which implies

Thus

**(iii) **Since every prime no. has only two factors 1 and number itself. This implies

** **

**2. Write the following sets in the roaster form:**

**(i) **

**(ii) **

**(iii) **

**Sol. (i)** On solving , we get , which implies either or .

Thus

**(ii) ** implies

It gives .

Thus .

**(iii) ** We have

This implies .

Therefore .

**Q3. If . Write in the roaster form.**

sol. **.**

Since is prime number , it has only two factors 1 and ( ) and the factors of are 1,2,2^{2},2^{3},…, . Therefore .

**Q4**. **, and are subsets of Universal Set . If and is the set of all whole numbers, draw a Venn diagram showing the relation of and .**

**Sol. **Here

Therefore , , and .

Hence, the Venn diagram showing relation of given sets is:

** **

**5. Determine whether the statement given below is true or false. Justify your answer.**

** For all sets , and , **

**Solution: **Let **, **

then . This implies …………..(i)

Now , this implies …………..(ii)

From (i) and (ii) , it is clear that .

We can also show that the given expression is false by using Venn Diagrams

Now, from the Venn diagrams, it is clear that .