I am horrible at percentages and I keep getting 15.805% as the answer to the question posed in the title, but according to others that is wrong and the answer is 6.33%. I can't wrap my head around this. Can someone please help to explain it? Thanks.:)
Edit: I got 15.805% by taking 316.1 and dividing it by 20. I thought it was the right way because I then took 20 and multiplied it by 15.805 to get 316.1
You can use the formulas and formulations that have already been given in the other answers. But trying to explain it intuitively:
You have a certain amount, which is called "$100\%$". Then you can compute what "$1\%$" is, by dividing the original amount by $100$. In your example, you have $316.1$, which is $100\%$, and you can divide it by $100$ to obtain $3.161$, which is $1\%$.
Now, you want to know "how many of these $1\%$'s do fit into $20$?".
So you can compute $20 / 3.161$, and see that the result is $6.33\%$
(I always wondered why "calculating with percentages" was taught like it was different from "normal" calculations. It is not. It's just breaking everything down into hundredths...)