jmc

Let's start by rewriting this problem into equation form:

$$\begin{array}{rl}x+y& =50,\\ x-y& =6.\end{array}$$

We want to find $xy$, so let's find $x$ and $y$ separately.

Begin by adding the two equations: $$\begin{array}{rl}2x& =56\\ x& =28\end{array}$$ Now, subtract the two equations $$\begin{array}{rl}2y& =44\\ y& =22\end{array}$$

So then $x\cdot y=22\cdot 28=\boxed{616}$