Question

The number of common terms to the two sequences $17,21,25$, ___, $417$ and $16,21,26$, ____, $466$ is

Answer 1

Answer: 20

Common terms will be $21,41,61$, ______
$21+(n-1)20\le 417$
$\Rightarrow n\le 20.8$
$\Rightarrow n=20$