ξ= {
26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44 } as
x is a natural number between
25
and
45.
A= { 26,28,30,32,34,36,38,40,42,44 } as A is set of a multiple of 3
within the limits of the universal set already defined as ξ.
⇒n(A)=10 as there are 10 elements in the Set A.
And, B= { 27,30,33,36,39,42 } as B is a set of multiple of 3 within the limits of the universal set already defined as ξ.
⇒n(B)=6 as there are 6 elements in the Set B.
Now, A−B= { 26,28,32,34,38,40,44 }
⇒n(A−B)=7