Question

QUESTOn two

let A and B be two finite set such that n(A) = 20
n(B) = 28 and n (AUB) = 35, find n (
A U B)​

Answer 1

Question Correction

Let A and B be two finite set such that n(A) = 20 , n(B) = 28 and n(AUB)=35, Find
`n(A \cap B)`

Answer:

`n(A \cap B)=13`

Explanation:

Given two finite sets such that:

`n(A) = 20\\n(B) = 28\\n (A \cup B) = 35`

We are to determine
`n(A \cap B)`.

Now, by set theory

`n (A \cup B)=n(A)+n(B)-n(A \cap B)\\35=20+28-n(A \cap B)\\35=48-n(A \cap B)\\n(A \cap B)=48-35\\n(A \cap B)=13`