Point B is halfway between A and C. The distance from C to D is the same as the distance from D to E, which is the same as the distance from E to F. The area of triangle ACF is 180 cm². How many square centimeters is the shaded area of triangle BCE?

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?