If for $\alpha \in N, \alpha N=\{a x: x \in N\}$, then the set $6 N \cap 8 N$ is equal to
Answer & explanation
Correct answer: option 4
$6 N \cap 8 N =\{6,12,18,24,30, ...) \cap\{8,16,24,32 ...\}$
= {24, 48, ....} = 24 N
Alternatively, L.C.M. of 6 and 8 = 24
∴ $6 N \cap 8 N = 24 N$
Hence (4) is the correct answer