Question

Find the union of each of the following pairs of sets: (i) X = {1, 3, 5} Y = {1, 2, 3} (ii) A = { a , e , i , o , u } B = { a , b , c } (iii) A = { x : x is a natural number and multiple of 3} B = { x : x is a natural number less than 6} (iv) A = { x : x is a natural number and 1 < x ≤ 6} B = { x : x is a natural number and 6 < x < 10} (v) A = {1, 2, 3}, B = Φ

Answer 1

(i)

The given pair of sets is X={ 1,3,5 } and Y={ 1,2,3 }.

The union of these sets is,

X∪Y={ 1,2,3,5 }

(ii)

The given pair of sets is A={ a,e,i,o,u } and B={ a,b,c }.

The union of these sets is,

A∪B={ a,b,c,e,i,o,u }.

(iii)

The given pair of sets is A={ x:x is a natural number and multiple of 3 } and B={ x:x is a natural number less than 6 }.

Then, the set A becomes,

A={ 3,6,9,… }

And the set B becomes,

B={ 1,2,3,4,5 }

The union of these sets is,

A∪B={ 1,2,4,5,or a multiple of 3 }.

(iv)

The given pair of sets is A={ x:x is a natural number and 1<x≤6 } and B={ x:x is a natural number and 6<x<10 }.

Then, the set A becomes,

A={ 2,3,4,5,6 }

And the set B becomes,

B={ 7,8,9 }

The union of these sets is,

A∪B={ 2,3,4,5,6,7,8,9 }

(v)

The given pair of sets is A={ 1,2,3 } and B=ϕ.

The union of these sets is A∪B={ 1,2,3 }.