Hi John,
I am going to show you two ways to approach this problem.
 First approach
 Think of each video game on a CD. Mel takes his CDs and puts them in a pile. Jamie has twice as many CDs so she can make two piles, each as tall as Mel's pile. Thus you have three piles of CDs, each containing the same number of CDs. There are 24 CDs in total. How many CDs are in each pile?
 Second approach
 I think you are expected to use algebra so here is an approach, essentially the same as the first approach but using algebraic notation.
Suppose that Mel has $x$ video games and thus Jamie has $2x$ video games. Thus, together they have $x + 2x = 3x$ video games. But they have 24 video games in total and hence $3x = 24.$ Solve for $x.$
I hope this helps
Penny
