#1**+1 **

Name your desired number as *x*. If 20% of *x* is equal to 81, we can write:

\(0.20x = 81\)(do you see how I got here?)

The way you reach this expression is because 20% is equivalent to 20 * 1/100, which is just 20/100, which is equivalent to 0.20

Then, we realize that if we multiply this by 5, we just get:

\(x= 405\)

That gives us our desired answer.

jfan17 Mar 25, 2020