Hola chicas Busco novia entre 13,14 o 15 que sea bonita y tenga redes sociales, manden fotos en la respuesta es que me ha pasado que responden personas que nd que ver ejje

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?