Sicily is playing a game where she is trying to guess the four digits in her friend's locker code, in any order. the digits range from 1 to 20, and none of the digits are repeated. if sicily makes 6 guesses, what is the probability that she will make a winning guess?

I think that the answer is 83.3%, because if you take the amount of digits, being 20 and divided that by the amount of digits, being 4, and then took the answer from there which is 5 and divided that by the number of guesses which is 6 and multiplied that answer by 100 and got 83.3%