If $A = \{x: x = 4n, n ∈ Z\}$ and $B=\{x: x = 6n, n∈ Z\}$, then $A∩B =$
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $\{x: x = 12n, n∈ Z\}$
We have,
$x∈A∩B$
$⇒ x = 4n$ and $x = 6n, n ∈ Z$
⇒ $x$ is a multiple of 4 and $x$ is a multiple of 6
⇒ $x$ is a multiple of 4 and 6 both
⇒ $x$ is a multiple of 12
$⇒ x = 12n, n∈ Z$
Hence, $A∩B = \{x: x = 12n, n ∈ Z\}$