Question

(3) If n(A) = 15. n(
AB) = 29, n(
AB) = 7, then n(B) = ?​

Answer 1

Step-by-step explanation:

$n(A∪B)=29 \\ n(A∩B)=7 \\ \\⇒n(A∪B)=n(A)+n(B)−n(A∩B) \\⇒29=15+n(B)−7 \\ ⇒n(B)=29−15+7 \\ =14+7 \\ =21 \\ ∴n(B)=21$