Question

Practice set 1( mathamatics)
Important for jee mains exam ​

Answer 1

Let x be the number of families having both radio and TV.

Total families = 1003

families which has neither radio nor TV = 63

families which has radio = 794

families which has TV = 187

let A be the set of families having radio and B be the set of families having TV.

→n(A) = 794

→n(B) = 187

→n(A∪B) = 1003 - 63 = 940

→n(A∩B) = x

Now,

n(A∪B) = n(A) + n(B) - n(A∩B)

→ 940 = 794 + 187 - x

→ 940 = 981 - x

→ x = 981 - 940

∴ x = 41