$X$ follows a binomial distribution with $n = 7$ and $p = 0.4$. Which expression is $P(X = 3)$?

Explanation

1. 01

   $P(X = r) = {}^{n}C_{r}\,p^{r}q^{n - r}$, with $q = 1 - p = 0.6$.

2. 02

   For $r = 3$: ${}^{7}C_{3}\,(0.4)^{3}(0.6)^{4}$.