Marissa is baking chocolate chip cookies. She has a total of 7 1/3 cups of chocolate chips. If each batch of cookies uses 2/3 of a cup of chocolate chips enter the greatest number of batches of cookies she can bake

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?