A random variable $X$ takes the values 0, 1, 2 and 3 with probabilities $k$, $3k$, $4k$ and $2k$. What is $k$?

Explanation

1. 01

   The probabilities of a distribution add up to 1: $k + 3k + 4k + 2k = 10k = 1$.

2. 02

   So $k = 0.1$.