A student creates a triangle with a perimeter of 13 inches. According to the student, the longest side is 9 inches. Explain how you know the student is incorrect. Can someone please help, i’ll mark brainliest!!

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?