Hi there-
It sounds like you're referring to our Challenge Problem Archive. This is a bank of 700+ level math questions. You can purchase that here on our website:
http://www.manhattangmat.com/storeitems ... 61&catid=4
Good luck studying and let me know if you have any other questions!
Best,
Brie Truesdell
Student Services Associate
800-576-4628
studentservices@manhattangmat.com
www.manhattangmat.com