determine the constant c so that p(x,y) satisfies the conditions of being a joint probability mass function for two discrete random variables $p(x,y)=c(2x+y)$, where $x=1,2, y=1,2,3$
Total probability is $\sum p(x,y)=1 $, and the sample space is $(1,1),(1,2),(1,3),(2,1),(2,2),(2,3)$. So the sum is
$$3c+4c+5c+5c+6c+7c=1 \\ \implies c=\frac{1}{30}$$
Is this how we get?