Please help asap. The first one is either less than 0 or great than 0, the second one is either 1 real, 2 real, or 2 imaginary, and the last one is either less than 0 or greater than 0.

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?