Question

11. If X={ x:x is a prime number which is less than 15} Y={y: y is a multiple of 7,753330)
then find i) n(X), ii) n( Y) and iii) n (X-Y)​

Answer 1

Step-by-step explanation:

Given:-

X={ x:x is a prime number which is less than 15} Y={y: y is a multiple of 7,753330)

To find:-

Find i) n(X), ii) n( Y) and iii) n (X-Y) ?

Solution:-

Given sets are :

X={ x:x is a prime number which is less than 15}

X ={ 2,3,5,7,11,13 }

The number of elements in the set X = 6

n(X) = 6

Y={y: y is a multiple of 7,753330}

Y ={ 7753330 , 15506660, ...}

The number of elements in the set Y = Countless

= Infinite number of elements

n(Y) = infinite

X - Y

= { 2,3,5,7,11,13 } - { 7753330 , 15506660, ...}

= { 2,3,5,7,11,13 }

The number of elements in the set X-Y = 6

n(X-Y) = 6

Answer:-

I) n(X) = 6

ii) n(Y) = infinite

iii) n(X-Y) = 6

Used formulae:-

• The number of elements in a set A is called Cardinal number of A and it is denoted by n(A).
• The numbers obtained by multiplying with 1,2,3... are called multiples of the given number.
• Every number has infinite number of multiples.
• The set of elements in only belongs to A not belongs to B is called the difference of A and B and it is denoted by A-B