About A 100-page document is being printed by four printers. Each page will be printed exactly once.

Suppose that all the pages are black-and-white, but each group of 25 consecutive pages (1-25, 26-50, 51-75, 76-100) must be assigned to the same printer. Each printer can be assigned 0, 25, 50, 75, or 100 pages to print. How many ways are there for the 100 pages to be assigned to the four printers?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?