The total amount of money (in cents) in x quarters, left parenthesis x plus 5 right parenthesis dimes, and 3x nickels. (hint: the value of a quarter is 25 cents, the value of a dime is 10 cents, and the value of a nickel is 5 cents.)

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?