For a particular chemical reaction the rate (g/hr) at which one of the reactants changes is proportional to the amount of that reactant present. If P represents the amount of that reactant at time t, Upper P prime (t )equalsminus0.07P(t). There are 60 grams of the reactant when the process starts.

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?