Answer:
23.3%
Explanation:
Wow, that's definitely a confusing way to teach it. Let me help you understand it:
7 is what percent of 30? This is:
7 / 30 or

We are going to do cross multiplication to find the missing value, X.

30 * X = 100 * 7
30X = 700
X =

X = 23.3 % is the missing value