ML AGGARWAL CLASS 7 Chapter 5 Sets EXERCISE 5.1

 EXERCISE:5.1

Question 1

i) All state of India 

ii) Last three days of a week 

iii) All months of a year having at least 30 days 

The above three are set because they are well defined 

Remaining all are not sets, they are not well defined 

Question 2

(iii) and (iv) are two 

(i) is false because C is not a vowel

(ii) is false because {a} is a set and not element 

(iii) is false because b is not vowel , so $b \notin A$ of course , $a \in A$

(v) is false , {a,i ,u} is a set and not elements 

Question 3

(i)The set of first six letters of alphabet

ii) {prime numbers less than 20 }

iii) {last three days of a weet }

iv) {months of a year whose name being with a vowel}

Question 4

i) $\{12,14,16,18,20,22 \ldots \ldots, 48\}$ ;$\{x: x=2 n, n \in N$ and $5<n<25$}

ii) { Jan, Mar, may, July, Aug, oct, Dec }

{$x \mid x$ is a month of a year having more than 30 days}

iii) {0,1,4,9},{x $\mid x$ is a perfect square one digit number}

iv) {1,2,3,4,6,9,12,18,36} ;{x $\mid x$ is a factrr of  36}

Question 5

i) {0,4,8 ,8,12,16}; {whole numbers which are divisible by 4 and less than 20}

ii) {1,4,9,16,25,36,49};{square of first seven natural number}

iii) {-1,1,3,5,7};{odd integers which lie between -2 and 8}

iv) {U,L,T,I,M,A};{letters in the word ULTIMATUM}

Question 6

i) $\{5,6,7,8,9\}$

ii) $\{-12,-6,0,6,12\}$

iii) $\{0,3,8,15\}$

iv) $\{1\}$

V) $\{N, T\}$

vi) $\{1,0,5,6,7\}$

Question 7

i) {x:x is an odd natural number and $x<30$}

ii) {$x \mid x$ is a prime number and $x<30$}

iii) $\left\{x \mid x=n^{2}, n \in N\right\}$

iv) $\left\{x \mid x=\frac{1}{n}, \quad \eta \in N\right.$ and $\left.5 \leq n \leq 20\right\}$

v) $\{x \mid x=s p, p \in I$ and $-2 \leq p \leq 5\}$

vi) $\{x: x$ is a month of a year whose name beings with letter 'J'

Question 8

i) {Vowels in the word COMPETITION}

ii) {x: x is a vowel in the word COMPETITION}

iii) {O,E,I}