Sarah K. answered 03/28/19
Tutor for the SAT for over 10 years
Let's start with some vocabulary.
Percent means per (for every) cent (100).
"What percent" can translate to what (value) of 'x' for every 100.... x/100.
We can break down the sentence to understand where to place variables by translating it like a foreign language!
5 is (=) what (x) percent (over 100) of (multiply by) 20?
5 = (x/100) • 20
We want to solve for x, the "what" in what percent.
Divide both sides by 20 to get: 5/20 = x/100
Now we have a proportion.
You can solve for x by cross multiplying 100 • 5 and then dividing by 20 to get x = 25.
Remember that while x is 25, it represents a percent, 5 is 25% of 20.