Eliza has 24 black and white photographs and 72 photographs in color she is arranging the for the girls and in Alabama once each page to contain the same combination of color and black-and-white photographs

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?