The bottom of a 13-foot straight ladder is set into the ground 2.5 feet away from a wall. When the top of the ladder is leaned against the wall, what is the distance above the ground it will reach? Round to the nearest tenth.

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?