Question

What is A ∪ B for two mutually exclusive sets A and B?

(a) n (A) + n (B)

(b) n (A) – n (B)

(c) n (B) – n (A)

(d) n (A) * n (B)

I had been asked this question in an interview for job.

This question is from Practical Problems on Union and Intersection of Two Sets in portion Sets of Mathematics – Class 11

Answer 1

Right option is (a) n (A) + n (B)

For explanation: We know, n (A ∪ B) = n (A) + n (B) – n (A ∩ B).

For mutually exclusive sets A ∩ B=Φ i.e. n (A ∩ B)=0.

n (A ∪ B) = n (A) + n (B).