Question

if n (a) =5, n(A U B) =9, n (A INTERSECTION B)= B THEN FIND N (B)
1. 2
2.4
3.6
4.8​

Answer 1

Answer:

n(A∪B)=n(A)+n(B)−n(A∩B)−−−−−−−(1)

Given n(A)=7

n(B)=9

n(A∪B)=14

Substituting in 1

14=7+9−n(A∩B)

⇒n(A∩B)=16−14=2

Answer 2

Step-by-step explanation:

n(A U B) = n(A) + n(B) + n(A intersection B)

9 = 5 + n (B) + n (B)

4 = 2n(B)

n( B) = 2

Hope it helps. If value of n(A intersection B) is something else. Put that value in 1st equation and then solve.