Question

Find the following set is singleton set or not.

B = {$y$ : $2y+1<3$ and $YϵW$}

Answer 1

A singleton set has only one element.
$2y+1<3$
$=>2y<2$
$=>y<1$
A whole number less than $1$ is $0$
Hence, $y=0$
Since $y$ has a single value, Set $B$ is a singleton set.