Problem Before sending track and field athletes to the Olympics, the U. S. holds a qualifying meet.
The lower dot plot shows the times (in seconds) of the 888 sprinters who competed in the final of the women's 100100100-meter dash at the 201220122012 Olympic games. The upper dot plot shows the times (in seconds) of the top 888 sprinters at the U. S. qualifying meet for that event.

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?