Question

List the total number of elements in the following set :

{$x$ : $x=2y+5$ ; $yϵN$ and $2\le y<6$}

Answer 1

Values of $y$ satisfying the given condition are $2,3,4,5$
Corresponding values of $x$ are $2\left(2\right)+5,2\left(3\right)+5,2\left(4\right)+5,2\left(5\right)+5=9,11,13,15$
Hence, elements of the set $9,11,13,15$

$\therefore$ Total number of elements in the set are $4$.