Let's say the debt in the united states is now near 1.8 × 10^13 dollars and that there are about 300,000,000 people in the united states. if every person paid their fair share of the debt, approximately how much would that be per person?

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?