Ineed for this one do i add them up and equal them to 180?

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?

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3

Ihonestly have no clue if it's each or none.