Sets Relations And Functions Question 22
Question: Out of 32 persons, 30 invest in national savings certificates and 17 invest in shares. What is the number of persons who invest in both?
Options:
A) 13
B) 15
C) 17
D) 19
Show Answer
Answer:
Correct Answer: B
Solution:
- [b]Let N = National savings certificates
S = Shares
Total no. of persons = 32
No. of persons who invest in national
Savings certificates = 30
No. of persons who invest in shares = 17
Therefore
$ n(N\cup S)=32,n(N)=30,n(S)=17 $
We know that, $ n(N\cup S)=n(N)+n(S)-n(N\cap S) $
$ \Rightarrow 32=30+17-n(N\cup S) $
$ \Rightarrow n(N\cap S)=47-32=15 $
BETA
