a and b are two sets such that
n(a-b)=20+x
n(b-a)=3x
n(a∩b) =x+1 if n(a)= n(b)
the value of x
n(a-b)=20+x
n(b-a)=3x
n(a∩b) =x+1
We know that
n(a-b) = n(a)-n(a∩b)
∴n(a) = n(a-b) + n(a∩b)
= (20+x) + (x + 1)
= 2x + 21
Similarly, n(b) = n(b-a) + n(a∩b)
=3x + (x+1)
=4x + 1
According to the question,
n(a) = n(b)
∴2x + 21 = 4x +1
⇒2x = 20
∴x = 10