This weekend, jerome earned 252.50 in all. whhat was the dollar amount of the meals that jerome served. jerome earns 15%percent off all the costs of meal on all meals and he earns 80 dollars every weekend

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?