Two runners are to race one lap on a circular track. the radius to the inside track. the radius to the inside lane is 50 meters. the radius to the outside lane is 51 meters. how much of a head start should the runner on the outside get?

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?