My question says, A volunteer group is holding elections for President, Secretary, and Treasurer. If there are 20 people in the group what is the probability that Sam, Isaac, and Luke are the ones chosen?
My work so far is, 3C3 = 1, so there is only one way that Sam, Isaac, and Luke are the ones chosen for the President, Secretary, and Treasurer.
20C3 = 1140, so there are 1140 different ways to pick the President, Secretary, and Treasurer from a group of 20.
P (S, I, L all chosen) = 3C3 / 20C3 = 1 / 1140 But I'm stuck here because I don't know how to simplify the fraction 1 / 1140 into a percentage and I don't know if my work so far is correct.
It won't always be a finite decimal, like $\displaystyle \frac{5}{8}=0.625=62.5\%$.
In this case, $\displaystyle \frac{1}{1140}=0.000\overline{87719298245614035}$, but we can just round to $0.0008772$, or $0.08772\%$.