Answer
$8$ is $40$% of $20$.
Work Step by Step
We start by translating the statement.
"$8$ is" means "$8$ ="
"$40$% of what number" means "$40$%($x$)"
We put both parts of the statement together to get:
$8$ = $40$%($x$)
We want to change the $40$% into a decimal to be able to work with it more easily. We do this by taking the % sign off and moving the decimal point two places to the left:
$$8 = 0.40x$$
Divide both sides by $0.40$ to isolate $x$:
$$x = 20$$
