The baseball team needs new equipment Company A can provide 9 helmets, 6 bats, and 12 balls for $525 Company B can provide 10 helmets, bats, and 10 balls for $600. Company C can provide 8 helmets 5 bats, and 15 balls for $500 Which system of equations matches the equipment choices available for purchase?

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?