Question

If n(A) = 30, n(A U B) = 29 ,n( A ñ B) = 9 then n(B) = ?

Answer 1

Answer:

Given:

n(a)=15

n(a\cup ba∪b )=29

n(a\cap ba∩b )=7

To find:

n(b)

Solution:

We know that

n(a\cup ba∪b )=n(a)+n(b)-n(n\cap bn∩b )

To find the value of b we are using the above formula

Now, substitute the values then, we get

29=15+n(b)-729=15+n(b)−7

n(b)=29-15+7n(b)=29−15+7

n(b)=21n(b)=21

Hence, the value of n(b)=21