Source: http://www.billboard.com/#/news/jay-z-still-reigns-on-billboard-200-muse-1004014998.story
Discluding the demos and mixes: 134 with the covers "paranoid" and "no more mr. nice guy" 136
Megadeth has 12 studio albums.
a lot
A Platinum record is one million copies sold of a single or an album. A gold record is 500,000 copies sold single or album. Silver is only used in some countries.
Just one.