Question

In a committee, 40 person can speak Hindi 20 can speak English and 10 can speak both languages. Find how many persons can speak atleast one language ?

Answer 1

Let A = set of person who speak Hindi and B = set of person who speak English
`:. n(A)=40,n(B)=20 and n(A capB)=10`
Now, `n(A cupB)=n(A)+n(B)-n(A capB)`
`= 40 +20 - 10 = 50`
`:.` No. of persons who speak atleast one language.
`= 50`.