ThmDex – An index of mathematical definitions, results, and conjectures.
P3668
The first claim is clear. For the second, consider what values each side can attain. The random variable $2 X$ can attain values only in the set $\{ 0, 2 \}$, while the random variable $X + Y$ can attain values in the set $\{ 0, 1, 2 \}$. $\square$