More Discs. After cleaning house, Josh took a box of 29 used discs to sell at the flea market. Some were computer games (which he sold for $2 each), some were music CDs (which he sold
for $3 each), and the rest were video DVDs (which he sold for $4 each). If Josh sold everything
(which included twice as many DVDs as computer games), and he made a total of $93, how
many of each type of disc did he sell?